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src/gleam@list.erl

-module(gleam@list).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).
-export([length/1, reverse/1, is_empty/1, contains/2, first/1, rest/1, filter/2, filter_map/2, map/2, map2/3, index_map/2, try_map/2, drop/2, take/2, new/0, wrap/1, append/2, prepend/2, flatten/1, flat_map/2, fold/3, count/2, group/2, map_fold/3, fold_right/3, index_fold/3, try_fold/3, fold_until/3, find/2, find_map/2, all/2, any/2, zip/2, strict_zip/2, unzip/1, intersperse/2, unique/1, sort/2, range/2, repeat/2, split/2, split_while/2, key_find/2, key_filter/2, key_pop/2, key_set/3, each/2, try_each/2, partition/2, permutations/1, window/2, window_by_2/1, drop_while/2, take_while/2, chunk/2, sized_chunk/2, reduce/2, scan/3, last/1, combinations/2, combination_pairs/1, transpose/1, interleave/1, shuffle/1, max/2, sample/2]).
-export_type([continue_or_stop/1, sorting/0]).
-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.
?MODULEDOC(
" Lists are an ordered sequence of elements and are one of the most common\n"
" data types in Gleam.\n"
"\n"
" New elements can be added and removed from the front of a list in\n"
" constant time, while adding and removing from the end requires traversing\n"
" and copying the whole list, so keep this in mind when designing your\n"
" programs.\n"
"\n"
" There is a dedicated syntax for prefixing to a list:\n"
"\n"
" ```gleam\n"
" let new_list = [1, 2, ..existing_list]\n"
" ```\n"
"\n"
" And a matching syntax for getting the first elements of a list:\n"
"\n"
" ```gleam\n"
" case list {\n"
" [first_element, ..rest] -> first_element\n"
" _ -> \"this pattern matches when the list is empty\"\n"
" }\n"
" ```\n"
"\n"
).
-type continue_or_stop(YP) :: {continue, YP} | {stop, YP}.
-type sorting() :: ascending | descending.
-file("src/gleam/list.gleam", 61).
-spec length_loop(list(any()), integer()) -> integer().
length_loop(List, Count) ->
case List of
[_ | List@1] ->
length_loop(List@1, Count + 1);
[] ->
Count
end.
-file("src/gleam/list.gleam", 57).
?DOC(
" Counts the number of elements in a given list.\n"
"\n"
" This function has to traverse the list to determine the number of elements,\n"
" so it runs in linear time.\n"
"\n"
" This function is natively implemented by the virtual machine and is highly\n"
" optimised.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" length([])\n"
" // -> 0\n"
" ```\n"
"\n"
" ```gleam\n"
" length([1])\n"
" // -> 1\n"
" ```\n"
"\n"
" ```gleam\n"
" length([1, 2])\n"
" // -> 2\n"
" ```\n"
).
-spec length(list(any())) -> integer().
length(List) ->
erlang:length(List).
-file("src/gleam/list.gleam", 131).
-spec reverse_and_prepend(list(YZ), list(YZ)) -> list(YZ).
reverse_and_prepend(Prefix, Suffix) ->
case Prefix of
[] ->
Suffix;
[First | Rest] ->
reverse_and_prepend(Rest, [First | Suffix])
end.
-file("src/gleam/list.gleam", 126).
?DOC(
" Creates a new list from a given list containing the same elements but in the\n"
" opposite order.\n"
"\n"
" This function has to traverse the list to create the new reversed list, so\n"
" it runs in linear time.\n"
"\n"
" This function is natively implemented by the virtual machine and is highly\n"
" optimised.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" reverse([])\n"
" // -> []\n"
" ```\n"
"\n"
" ```gleam\n"
" reverse([1])\n"
" // -> [1]\n"
" ```\n"
"\n"
" ```gleam\n"
" reverse([1, 2])\n"
" // -> [2, 1]\n"
" ```\n"
).
-spec reverse(list(YW)) -> list(YW).
reverse(List) ->
lists:reverse(List).
-file("src/gleam/list.gleam", 159).
?DOC(
" Determines whether or not the list is empty.\n"
"\n"
" This function runs in constant time.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" is_empty([])\n"
" // -> True\n"
" ```\n"
"\n"
" ```gleam\n"
" is_empty([1])\n"
" // -> False\n"
" ```\n"
"\n"
" ```gleam\n"
" is_empty([1, 1])\n"
" // -> False\n"
" ```\n"
).
-spec is_empty(list(any())) -> boolean().
is_empty(List) ->
List =:= [].
-file("src/gleam/list.gleam", 195).
?DOC(
" Determines whether or not a given element exists within a given list.\n"
"\n"
" This function traverses the list to find the element, so it runs in linear\n"
" time.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" [] |> contains(any: 0)\n"
" // -> False\n"
" ```\n"
"\n"
" ```gleam\n"
" [0] |> contains(any: 0)\n"
" // -> True\n"
" ```\n"
"\n"
" ```gleam\n"
" [1] |> contains(any: 0)\n"
" // -> False\n"
" ```\n"
"\n"
" ```gleam\n"
" [1, 1] |> contains(any: 0)\n"
" // -> False\n"
" ```\n"
"\n"
" ```gleam\n"
" [1, 0] |> contains(any: 0)\n"
" // -> True\n"
" ```\n"
).
-spec contains(list(AAF), AAF) -> boolean().
contains(List, Elem) ->
case List of
[] ->
false;
[First | _] when First =:= Elem ->
true;
[_ | Rest] ->
contains(Rest, Elem)
end.
-file("src/gleam/list.gleam", 222).
?DOC(
" Gets the first element from the start of the list, if there is one.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" first([])\n"
" // -> Error(Nil)\n"
" ```\n"
"\n"
" ```gleam\n"
" first([0])\n"
" // -> Ok(0)\n"
" ```\n"
"\n"
" ```gleam\n"
" first([1, 2])\n"
" // -> Ok(1)\n"
" ```\n"
).
-spec first(list(AAH)) -> {ok, AAH} | {error, nil}.
first(List) ->
case List of
[] ->
{error, nil};
[First | _] ->
{ok, First}
end.
-file("src/gleam/list.gleam", 251).
?DOC(
" Returns the list minus the first element. If the list is empty, `Error(Nil)` is\n"
" returned.\n"
"\n"
" This function runs in constant time and does not make a copy of the list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" rest([])\n"
" // -> Error(Nil)\n"
" ```\n"
"\n"
" ```gleam\n"
" rest([0])\n"
" // -> Ok([])\n"
" ```\n"
"\n"
" ```gleam\n"
" rest([1, 2])\n"
" // -> Ok([2])\n"
" ```\n"
).
-spec rest(list(AAL)) -> {ok, list(AAL)} | {error, nil}.
rest(List) ->
case List of
[] ->
{error, nil};
[_ | Rest] ->
{ok, Rest}
end.
-file("src/gleam/list.gleam", 293).
-spec update_group(fun((AAW) -> AAX)) -> fun((gleam@dict:dict(AAX, list(AAW)), AAW) -> gleam@dict:dict(AAX, list(AAW))).
update_group(F) ->
fun(Groups, Elem) -> case gleam_stdlib:map_get(Groups, F(Elem)) of
{ok, Existing} ->
gleam@dict:insert(Groups, F(Elem), [Elem | Existing]);
{error, _} ->
gleam@dict:insert(Groups, F(Elem), [Elem])
end end.
-file("src/gleam/list.gleam", 321).
-spec filter_loop(list(ABH), fun((ABH) -> boolean()), list(ABH)) -> list(ABH).
filter_loop(List, Fun, Acc) ->
case List of
[] ->
lists:reverse(Acc);
[First | Rest] ->
New_acc = case Fun(First) of
true ->
[First | Acc];
false ->
Acc
end,
filter_loop(Rest, Fun, New_acc)
end.
-file("src/gleam/list.gleam", 317).
?DOC(
" Returns a new list containing only the elements from the first list for\n"
" which the given functions returns `True`.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" filter([2, 4, 6, 1], fn(x) { x > 2 })\n"
" // -> [4, 6]\n"
" ```\n"
"\n"
" ```gleam\n"
" filter([2, 4, 6, 1], fn(x) { x > 6 })\n"
" // -> []\n"
" ```\n"
).
-spec filter(list(ABE), fun((ABE) -> boolean())) -> list(ABE).
filter(List, Predicate) ->
filter_loop(List, Predicate, []).
-file("src/gleam/list.gleam", 353).
-spec filter_map_loop(
list(ABS),
fun((ABS) -> {ok, ABU} | {error, any()}),
list(ABU)
) -> list(ABU).
filter_map_loop(List, Fun, Acc) ->
case List of
[] ->
lists:reverse(Acc);
[First | Rest] ->
New_acc = case Fun(First) of
{ok, First@1} ->
[First@1 | Acc];
{error, _} ->
Acc
end,
filter_map_loop(Rest, Fun, New_acc)
end.
-file("src/gleam/list.gleam", 349).
?DOC(
" Returns a new list containing only the elements from the first list for\n"
" which the given functions returns `Ok(_)`.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" filter_map([2, 4, 6, 1], Error)\n"
" // -> []\n"
" ```\n"
"\n"
" ```gleam\n"
" filter_map([2, 4, 6, 1], fn(x) { Ok(x + 1) })\n"
" // -> [3, 5, 7, 2]\n"
" ```\n"
).
-spec filter_map(list(ABL), fun((ABL) -> {ok, ABN} | {error, any()})) -> list(ABN).
filter_map(List, Fun) ->
filter_map_loop(List, Fun, []).
-file("src/gleam/list.gleam", 384).
-spec map_loop(list(ACE), fun((ACE) -> ACG), list(ACG)) -> list(ACG).
map_loop(List, Fun, Acc) ->
case List of
[] ->
lists:reverse(Acc);
[First | Rest] ->
map_loop(Rest, Fun, [Fun(First) | Acc])
end.
-file("src/gleam/list.gleam", 380).
?DOC(
" Returns a new list containing only the elements of the first list after the\n"
" function has been applied to each one.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" map([2, 4, 6], fn(x) { x * 2 })\n"
" // -> [4, 8, 12]\n"
" ```\n"
).
-spec map(list(ACA), fun((ACA) -> ACC)) -> list(ACC).
map(List, Fun) ->
map_loop(List, Fun, []).
-file("src/gleam/list.gleam", 411).
-spec map2_loop(list(ACP), list(ACR), fun((ACP, ACR) -> ACT), list(ACT)) -> list(ACT).
map2_loop(List1, List2, Fun, Acc) ->
case {List1, List2} of
{[], _} ->
lists:reverse(Acc);
{_, []} ->
lists:reverse(Acc);
{[A | As_], [B | Bs]} ->
map2_loop(As_, Bs, Fun, [Fun(A, B) | Acc])
end.
-file("src/gleam/list.gleam", 407).
?DOC(
" Combines two lists into a single list using the given function.\n"
"\n"
" If a list is longer than the other the extra elements are dropped.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" map2([1, 2, 3], [4, 5, 6], fn(x, y) { x + y })\n"
" // -> [5, 7, 9]\n"
" ```\n"
"\n"
" ```gleam\n"
" map2([1, 2], [\"a\", \"b\", \"c\"], fn(i, x) { #(i, x) })\n"
" // -> [#(1, \"a\"), #(2, \"b\")]\n"
" ```\n"
).
-spec map2(list(ACJ), list(ACL), fun((ACJ, ACL) -> ACN)) -> list(ACN).
map2(List1, List2, Fun) ->
map2_loop(List1, List2, Fun, []).
-file("src/gleam/list.gleam", 466).
-spec index_map_loop(
list(ADF),
fun((ADF, integer()) -> ADH),
integer(),
list(ADH)
) -> list(ADH).
index_map_loop(List, Fun, Index, Acc) ->
case List of
[] ->
lists:reverse(Acc);
[First | Rest] ->
Acc@1 = [Fun(First, Index) | Acc],
index_map_loop(Rest, Fun, Index + 1, Acc@1)
end.
-file("src/gleam/list.gleam", 462).
?DOC(
" Returns a new list containing only the elements of the first list after the\n"
" function has been applied to each one and their index.\n"
"\n"
" The index starts at 0, so the first element is 0, the second is 1, and so\n"
" on.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" index_map([\"a\", \"b\"], fn(x, i) { #(i, x) })\n"
" // -> [#(0, \"a\"), #(1, \"b\")]\n"
" ```\n"
).
-spec index_map(list(ADB), fun((ADB, integer()) -> ADD)) -> list(ADD).
index_map(List, Fun) ->
index_map_loop(List, Fun, 0, []).
-file("src/gleam/list.gleam", 520).
-spec try_map_loop(list(ADT), fun((ADT) -> {ok, ADV} | {error, ADW}), list(ADV)) -> {ok,
list(ADV)} |
{error, ADW}.
try_map_loop(List, Fun, Acc) ->
case List of
[] ->
{ok, lists:reverse(Acc)};
[First | Rest] ->
case Fun(First) of
{ok, First@1} ->
try_map_loop(Rest, Fun, [First@1 | Acc]);
{error, Error} ->
{error, Error}
end
end.
-file("src/gleam/list.gleam", 513).
?DOC(
" Takes a function that returns a `Result` and applies it to each element in a\n"
" given list in turn.\n"
"\n"
" If the function returns `Ok(new_value)` for all elements in the list then a\n"
" list of the new values is returned.\n"
"\n"
" If the function returns `Error(reason)` for any of the elements then it is\n"
" returned immediately. None of the elements in the list are processed after\n"
" one returns an `Error`.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" try_map([1, 2, 3], fn(x) { Ok(x + 2) })\n"
" // -> Ok([3, 4, 5])\n"
" ```\n"
"\n"
" ```gleam\n"
" try_map([1, 2, 3], fn(_) { Error(0) })\n"
" // -> Error(0)\n"
" ```\n"
"\n"
" ```gleam\n"
" try_map([[1], [2, 3]], first)\n"
" // -> Ok([1, 2])\n"
" ```\n"
"\n"
" ```gleam\n"
" try_map([[1], [], [2]], first)\n"
" // -> Error(Nil)\n"
" ```\n"
).
-spec try_map(list(ADK), fun((ADK) -> {ok, ADM} | {error, ADN})) -> {ok,
list(ADM)} |
{error, ADN}.
try_map(List, Fun) ->
try_map_loop(List, Fun, []).
-file("src/gleam/list.gleam", 555).
?DOC(
" Returns a list that is the given list with up to the given number of\n"
" elements removed from the front of the list.\n"
"\n"
" If the element has less than the number of elements an empty list is\n"
" returned.\n"
"\n"
" This function runs in linear time but does not copy the list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" drop([1, 2, 3, 4], 2)\n"
" // -> [3, 4]\n"
" ```\n"
"\n"
" ```gleam\n"
" drop([1, 2, 3, 4], 9)\n"
" // -> []\n"
" ```\n"
).
-spec drop(list(AED), integer()) -> list(AED).
drop(List, N) ->
case N =< 0 of
true ->
List;
false ->
case List of
[] ->
[];
[_ | Rest] ->
drop(Rest, N - 1)
end
end.
-file("src/gleam/list.gleam", 590).
-spec take_loop(list(AEJ), integer(), list(AEJ)) -> list(AEJ).
take_loop(List, N, Acc) ->
case N =< 0 of
true ->
lists:reverse(Acc);
false ->
case List of
[] ->
lists:reverse(Acc);
[First | Rest] ->
take_loop(Rest, N - 1, [First | Acc])
end
end.
-file("src/gleam/list.gleam", 586).
?DOC(
" Returns a list containing the first given number of elements from the given\n"
" list.\n"
"\n"
" If the element has less than the number of elements then the full list is\n"
" returned.\n"
"\n"
" This function runs in linear time.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" take([1, 2, 3, 4], 2)\n"
" // -> [1, 2]\n"
" ```\n"
"\n"
" ```gleam\n"
" take([1, 2, 3, 4], 9)\n"
" // -> [1, 2, 3, 4]\n"
" ```\n"
).
-spec take(list(AEG), integer()) -> list(AEG).
take(List, N) ->
take_loop(List, N, []).
-file("src/gleam/list.gleam", 610).
?DOC(
" Returns a new empty list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" new()\n"
" // -> []\n"
" ```\n"
).
-spec new() -> list(any()).
new() ->
[].
-file("src/gleam/list.gleam", 630).
?DOC(
" Returns the given item wrapped in a list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" wrap(1)\n"
" // -> [1]\n"
"\n"
" wrap([\"a\", \"b\", \"c\"])\n"
" // -> [[\"a\", \"b\", \"c\"]]\n"
"\n"
" wrap([[]])\n"
" // -> [[[]]]\n"
" ```\n"
).
-spec wrap(AEP) -> list(AEP).
wrap(Item) ->
[Item].
-file("src/gleam/list.gleam", 651).
-spec append_loop(list(AEV), list(AEV)) -> list(AEV).
append_loop(First, Second) ->
case First of
[] ->
Second;
[First@1 | Rest] ->
append_loop(Rest, [First@1 | Second])
end.
-file("src/gleam/list.gleam", 647).
?DOC(
" Joins one list onto the end of another.\n"
"\n"
" This function runs in linear time, and it traverses and copies the first\n"
" list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" append([1, 2], [3])\n"
" // -> [1, 2, 3]\n"
" ```\n"
).
-spec append(list(AER), list(AER)) -> list(AER).
append(First, Second) ->
lists:append(First, Second).
-file("src/gleam/list.gleam", 671).
?DOC(
" Prefixes an item to a list. This can also be done using the dedicated\n"
" syntax instead\n"
"\n"
" ```gleam\n"
" let existing_list = [2, 3, 4]\n"
"\n"
" [1, ..existing_list]\n"
" // -> [1, 2, 3, 4]\n"
"\n"
" prepend(to: existing_list, this: 1)\n"
" // -> [1, 2, 3, 4]\n"
" ```\n"
).
-spec prepend(list(AEZ), AEZ) -> list(AEZ).
prepend(List, Item) ->
[Item | List].
-file("src/gleam/list.gleam", 675).
-spec flatten_loop(list(list(AFC)), list(AFC)) -> list(AFC).
flatten_loop(Lists, Acc) ->
case Lists of
[] ->
lists:reverse(Acc);
[List | Further_lists] ->
flatten_loop(Further_lists, reverse_and_prepend(List, Acc))
end.
-file("src/gleam/list.gleam", 695).
?DOC(
" This is the same as `concat`: it joins a list of lists into a single\n"
" list.\n"
"\n"
" This function traverses all elements twice.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" flatten([[1], [2, 3], []])\n"
" // -> [1, 2, 3]\n"
" ```\n"
).
-spec flatten(list(list(AFH))) -> list(AFH).
flatten(Lists) ->
flatten_loop(Lists, []).
-file("src/gleam/list.gleam", 708).
?DOC(
" Maps the list with the given function into a list of lists, and then flattens it.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" flat_map([2, 4, 6], fn(x) { [x, x + 1] })\n"
" // -> [2, 3, 4, 5, 6, 7]\n"
" ```\n"
).
-spec flat_map(list(AFL), fun((AFL) -> list(AFN))) -> list(AFN).
flat_map(List, Fun) ->
_pipe = map(List, Fun),
flatten(_pipe).
-file("src/gleam/list.gleam", 721).
?DOC(
" Reduces a list of elements into a single value by calling a given function\n"
" on each element, going from left to right.\n"
"\n"
" `fold([1, 2, 3], 0, add)` is the equivalent of\n"
" `add(add(add(0, 1), 2), 3)`.\n"
"\n"
" This function runs in linear time.\n"
).
-spec fold(list(AFQ), AFS, fun((AFS, AFQ) -> AFS)) -> AFS.
fold(List, Initial, Fun) ->
case List of
[] ->
Initial;
[First | Rest] ->
fold(Rest, Fun(Initial, First), Fun)
end.
-file("src/gleam/list.gleam", 90).
?DOC(
" Counts the number of elements in a given list satisfying a given predicate.\n"
"\n"
" This function has to traverse the list to determine the number of elements,\n"
" so it runs in linear time.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" count([], fn(a) { a > 0 })\n"
" // -> 0\n"
" ```\n"
"\n"
" ```gleam\n"
" count([1], fn(a) { a > 0 })\n"
" // -> 1\n"
" ```\n"
"\n"
" ```gleam\n"
" count([1, 2, 3], int.is_odd)\n"
" // -> 2\n"
" ```\n"
).
-spec count(list(YU), fun((YU) -> boolean())) -> integer().
count(List, Predicate) ->
fold(List, 0, fun(Acc, Value) -> case Predicate(Value) of
true ->
Acc + 1;
false ->
Acc
end end).
-file("src/gleam/list.gleam", 289).
?DOC(
" Groups the elements from the given list by the given key function.\n"
"\n"
" Does not preserve the initial value order.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" import gleam/dict\n"
"\n"
" [Ok(3), Error(\"Wrong\"), Ok(200), Ok(73)]\n"
" |> group(by: fn(i) {\n"
" case i {\n"
" Ok(_) -> \"Successful\"\n"
" Error(_) -> \"Failed\"\n"
" }\n"
" })\n"
" |> dict.to_list\n"
" // -> [\n"
" // #(\"Failed\", [Error(\"Wrong\")]),\n"
" // #(\"Successful\", [Ok(73), Ok(200), Ok(3)])\n"
" // ]\n"
" ```\n"
"\n"
" ```gleam\n"
" import gleam/dict\n"
"\n"
" group([1,2,3,4,5], by: fn(i) { i - i / 3 * 3 })\n"
" |> dict.to_list\n"
" // -> [#(0, [3]), #(1, [4, 1]), #(2, [5, 2])]\n"
" ```\n"
).
-spec group(list(AAQ), fun((AAQ) -> AAS)) -> gleam@dict:dict(AAS, list(AAQ)).
group(List, Key) ->
fold(List, maps:new(), update_group(Key)).
-file("src/gleam/list.gleam", 436).
?DOC(
" Similar to `map` but also lets you pass around an accumulated value.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" map_fold(\n"
" over: [1, 2, 3],\n"
" from: 100,\n"
" with: fn(memo, i) { #(memo + i, i * 2) }\n"
" )\n"
" // -> #(106, [2, 4, 6])\n"
" ```\n"
).
-spec map_fold(list(ACW), ACY, fun((ACY, ACW) -> {ACY, ACZ})) -> {ACY,
list(ACZ)}.
map_fold(List, Initial, Fun) ->
_pipe = fold(
List,
{Initial, []},
fun(Acc, Item) ->
{Current_acc, Items} = Acc,
{Next_acc, Next_item} = Fun(Current_acc, Item),
{Next_acc, [Next_item | Items]}
end
),
gleam@pair:map_second(_pipe, fun lists:reverse/1).
-file("src/gleam/list.gleam", 743).
?DOC(
" Reduces a list of elements into a single value by calling a given function\n"
" on each element, going from right to left.\n"
"\n"
" `fold_right([1, 2, 3], 0, add)` is the equivalent of\n"
" `add(add(add(0, 3), 2), 1)`.\n"
"\n"
" This function runs in linear time.\n"
"\n"
" Unlike `fold` this function is not tail recursive. Where possible use\n"
" `fold` instead as it will use less memory.\n"
).
-spec fold_right(list(AFT), AFV, fun((AFV, AFT) -> AFV)) -> AFV.
fold_right(List, Initial, Fun) ->
case List of
[] ->
Initial;
[First | Rest] ->
Fun(fold_right(Rest, Initial, Fun), First)
end.
-file("src/gleam/list.gleam", 771).
-spec index_fold_loop(
list(AFZ),
AGB,
fun((AGB, AFZ, integer()) -> AGB),
integer()
) -> AGB.
index_fold_loop(Over, Acc, With, Index) ->
case Over of
[] ->
Acc;
[First | Rest] ->
index_fold_loop(Rest, With(Acc, First, Index), With, Index + 1)
end.
-file("src/gleam/list.gleam", 763).
?DOC(
" Like fold but the folding function also receives the index of the current element.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" [\"a\", \"b\", \"c\"]\n"
" |> index_fold([], fn(acc, item, index) { ... })\n"
" ```\n"
).
-spec index_fold(list(AFW), AFY, fun((AFY, AFW, integer()) -> AFY)) -> AFY.
index_fold(List, Initial, Fun) ->
index_fold_loop(List, Initial, Fun, 0).
-file("src/gleam/list.gleam", 803).
?DOC(
" A variant of fold that might fail.\n"
"\n"
" The folding function should return `Result(accumulator, error)`.\n"
" If the returned value is `Ok(accumulator)` try_fold will try the next value in the list.\n"
" If the returned value is `Error(error)` try_fold will stop and return that error.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" [1, 2, 3, 4]\n"
" |> try_fold(0, fn(acc, i) {\n"
" case i < 3 {\n"
" True -> Ok(acc + i)\n"
" False -> Error(Nil)\n"
" }\n"
" })\n"
" // -> Error(Nil)\n"
" ```\n"
).
-spec try_fold(list(AGC), AGE, fun((AGE, AGC) -> {ok, AGE} | {error, AGF})) -> {ok,
AGE} |
{error, AGF}.
try_fold(List, Initial, Fun) ->
case List of
[] ->
{ok, Initial};
[First | Rest] ->
case Fun(Initial, First) of
{ok, Result} ->
try_fold(Rest, Result, Fun);
{error, _} = Error ->
Error
end
end.
-file("src/gleam/list.gleam", 842).
?DOC(
" A variant of fold that allows to stop folding earlier.\n"
"\n"
" The folding function should return `ContinueOrStop(accumulator)`.\n"
" If the returned value is `Continue(accumulator)` fold_until will try the next value in the list.\n"
" If the returned value is `Stop(accumulator)` fold_until will stop and return that accumulator.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" [1, 2, 3, 4]\n"
" |> fold_until(0, fn(acc, i) {\n"
" case i < 3 {\n"
" True -> Continue(acc + i)\n"
" False -> Stop(acc)\n"
" }\n"
" })\n"
" // -> 3\n"
" ```\n"
).
-spec fold_until(list(AGK), AGM, fun((AGM, AGK) -> continue_or_stop(AGM))) -> AGM.
fold_until(List, Initial, Fun) ->
case List of
[] ->
Initial;
[First | Rest] ->
case Fun(Initial, First) of
{continue, Next_accumulator} ->
fold_until(Rest, Next_accumulator, Fun);
{stop, B} ->
B
end
end.
-file("src/gleam/list.gleam", 879).
?DOC(
" Finds the first element in a given list for which the given function returns\n"
" `True`.\n"
"\n"
" Returns `Error(Nil)` if no such element is found.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" find([1, 2, 3], fn(x) { x > 2 })\n"
" // -> Ok(3)\n"
" ```\n"
"\n"
" ```gleam\n"
" find([1, 2, 3], fn(x) { x > 4 })\n"
" // -> Error(Nil)\n"
" ```\n"
"\n"
" ```gleam\n"
" find([], fn(_) { True })\n"
" // -> Error(Nil)\n"
" ```\n"
).
-spec find(list(AGO), fun((AGO) -> boolean())) -> {ok, AGO} | {error, nil}.
find(List, Is_desired) ->
case List of
[] ->
{error, nil};
[First | Rest] ->
case Is_desired(First) of
true ->
{ok, First};
false ->
find(Rest, Is_desired)
end
end.
-file("src/gleam/list.gleam", 915).
?DOC(
" Finds the first element in a given list for which the given function returns\n"
" `Ok(new_value)`, then returns the wrapped `new_value`.\n"
"\n"
" Returns `Error(Nil)` if no such element is found.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" find_map([[], [2], [3]], first)\n"
" // -> Ok(2)\n"
" ```\n"
"\n"
" ```gleam\n"
" find_map([[], []], first)\n"
" // -> Error(Nil)\n"
" ```\n"
"\n"
" ```gleam\n"
" find_map([], first)\n"
" // -> Error(Nil)\n"
" ```\n"
).
-spec find_map(list(AGS), fun((AGS) -> {ok, AGU} | {error, any()})) -> {ok, AGU} |
{error, nil}.
find_map(List, Fun) ->
case List of
[] ->
{error, nil};
[First | Rest] ->
case Fun(First) of
{ok, First@1} ->
{ok, First@1};
{error, _} ->
find_map(Rest, Fun)
end
end.
-file("src/gleam/list.gleam", 950).
?DOC(
" Returns `True` if the given function returns `True` for all the elements in\n"
" the given list. If the function returns `False` for any of the elements it\n"
" immediately returns `False` without checking the rest of the list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" all([], fn(x) { x > 3 })\n"
" // -> True\n"
" ```\n"
"\n"
" ```gleam\n"
" all([4, 5], fn(x) { x > 3 })\n"
" // -> True\n"
" ```\n"
"\n"
" ```gleam\n"
" all([4, 3], fn(x) { x > 3 })\n"
" // -> False\n"
" ```\n"
).
-spec all(list(AHA), fun((AHA) -> boolean())) -> boolean().
all(List, Predicate) ->
case List of
[] ->
true;
[First | Rest] ->
case Predicate(First) of
true ->
all(Rest, Predicate);
false ->
false
end
end.
-file("src/gleam/list.gleam", 987).
?DOC(
" Returns `True` if the given function returns `True` for any the elements in\n"
" the given list. If the function returns `True` for any of the elements it\n"
" immediately returns `True` without checking the rest of the list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" any([], fn(x) { x > 3 })\n"
" // -> False\n"
" ```\n"
"\n"
" ```gleam\n"
" any([4, 5], fn(x) { x > 3 })\n"
" // -> True\n"
" ```\n"
"\n"
" ```gleam\n"
" any([4, 3], fn(x) { x > 4 })\n"
" // -> False\n"
" ```\n"
"\n"
" ```gleam\n"
" any([3, 4], fn(x) { x > 3 })\n"
" // -> True\n"
" ```\n"
).
-spec any(list(AHC), fun((AHC) -> boolean())) -> boolean().
any(List, Predicate) ->
case List of
[] ->
false;
[First | Rest] ->
case Predicate(First) of
true ->
true;
false ->
any(Rest, Predicate)
end
end.
-file("src/gleam/list.gleam", 1029).
-spec zip_loop(list(AHJ), list(AHL), list({AHJ, AHL})) -> list({AHJ, AHL}).
zip_loop(One, Other, Acc) ->
case {One, Other} of
{[First_one | Rest_one], [First_other | Rest_other]} ->
zip_loop(Rest_one, Rest_other, [{First_one, First_other} | Acc]);
{_, _} ->
lists:reverse(Acc)
end.
-file("src/gleam/list.gleam", 1025).
?DOC(
" Takes two lists and returns a single list of 2-element tuples.\n"
"\n"
" If one of the lists is longer than the other, the remaining elements from\n"
" the longer list are not used.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" zip([], [])\n"
" // -> []\n"
" ```\n"
"\n"
" ```gleam\n"
" zip([1, 2], [3])\n"
" // -> [#(1, 3)]\n"
" ```\n"
"\n"
" ```gleam\n"
" zip([1], [3, 4])\n"
" // -> [#(1, 3)]\n"
" ```\n"
"\n"
" ```gleam\n"
" zip([1, 2], [3, 4])\n"
" // -> [#(1, 3), #(2, 4)]\n"
" ```\n"
).
-spec zip(list(AHE), list(AHG)) -> list({AHE, AHG}).
zip(List, Other) ->
zip_loop(List, Other, []).
-file("src/gleam/list.gleam", 1070).
-spec strict_zip_loop(list(AHW), list(AHY), list({AHW, AHY})) -> {ok,
list({AHW, AHY})} |
{error, nil}.
strict_zip_loop(One, Other, Acc) ->
case {One, Other} of
{[], []} ->
{ok, lists:reverse(Acc)};
{[], _} ->
{error, nil};
{_, []} ->
{error, nil};
{[First_one | Rest_one], [First_other | Rest_other]} ->
strict_zip_loop(
Rest_one,
Rest_other,
[{First_one, First_other} | Acc]
)
end.
-file("src/gleam/list.gleam", 1063).
?DOC(
" Takes two lists and returns a single list of 2-element tuples.\n"
"\n"
" If one of the lists is longer than the other, an `Error` is returned.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" strict_zip([], [])\n"
" // -> Ok([])\n"
" ```\n"
"\n"
" ```gleam\n"
" strict_zip([1, 2], [3])\n"
" // -> Error(Nil)\n"
" ```\n"
"\n"
" ```gleam\n"
" strict_zip([1], [3, 4])\n"
" // -> Error(Nil)\n"
" ```\n"
"\n"
" ```gleam\n"
" strict_zip([1, 2], [3, 4])\n"
" // -> Ok([#(1, 3), #(2, 4)])\n"
" ```\n"
).
-spec strict_zip(list(AHP), list(AHR)) -> {ok, list({AHP, AHR})} | {error, nil}.
strict_zip(List, Other) ->
strict_zip_loop(List, Other, []).
-file("src/gleam/list.gleam", 1101).
-spec unzip_loop(list({AIJ, AIK}), list(AIJ), list(AIK)) -> {list(AIJ),
list(AIK)}.
unzip_loop(Input, One, Other) ->
case Input of
[] ->
{lists:reverse(One), lists:reverse(Other)};
[{First_one, First_other} | Rest] ->
unzip_loop(Rest, [First_one | One], [First_other | Other])
end.
-file("src/gleam/list.gleam", 1097).
?DOC(
" Takes a single list of 2-element tuples and returns two lists.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" unzip([#(1, 2), #(3, 4)])\n"
" // -> #([1, 3], [2, 4])\n"
" ```\n"
"\n"
" ```gleam\n"
" unzip([])\n"
" // -> #([], [])\n"
" ```\n"
).
-spec unzip(list({AIE, AIF})) -> {list(AIE), list(AIF)}.
unzip(Input) ->
unzip_loop(Input, [], []).
-file("src/gleam/list.gleam", 1136).
-spec intersperse_loop(list(AIT), AIT, list(AIT)) -> list(AIT).
intersperse_loop(List, Separator, Acc) ->
case List of
[] ->
lists:reverse(Acc);
[First | Rest] ->
intersperse_loop(Rest, Separator, [First, Separator | Acc])
end.
-file("src/gleam/list.gleam", 1129).
?DOC(
" Inserts a given value between each existing element in a given list.\n"
"\n"
" This function runs in linear time and copies the list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" intersperse([1, 1, 1], 2)\n"
" // -> [1, 2, 1, 2, 1]\n"
" ```\n"
"\n"
" ```gleam\n"
" intersperse([], 2)\n"
" // -> []\n"
" ```\n"
).
-spec intersperse(list(AIQ), AIQ) -> list(AIQ).
intersperse(List, Elem) ->
case List of
[] ->
List;
[_] ->
List;
[First | Rest] ->
intersperse_loop(Rest, Elem, [First])
end.
-file("src/gleam/list.gleam", 1159).
-spec unique_loop(list(AJA), gleam@dict:dict(AJA, nil), list(AJA)) -> list(AJA).
unique_loop(List, Seen, Acc) ->
case List of
[] ->
lists:reverse(Acc);
[First | Rest] ->
case gleam@dict:has_key(Seen, First) of
true ->
unique_loop(Rest, Seen, Acc);
false ->
unique_loop(
Rest,
gleam@dict:insert(Seen, First, nil),
[First | Acc]
)
end
end.
-file("src/gleam/list.gleam", 1155).
?DOC(
" Removes any duplicate elements from a given list.\n"
"\n"
" This function returns in loglinear time.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" unique([1, 1, 1, 4, 7, 3, 3, 4])\n"
" // -> [1, 4, 7, 3]\n"
" ```\n"
).
-spec unique(list(AIX)) -> list(AIX).
unique(List) ->
unique_loop(List, maps:new(), []).
-file("src/gleam/list.gleam", 1245).
?DOC(
" Given a list it returns slices of it that are locally sorted in ascending\n"
" order.\n"
"\n"
" Imagine you have this list:\n"
"\n"
" ```\n"
" [1, 2, 3, 2, 1, 0]\n"
" ^^^^^^^ ^^^^^^^ This is a slice in descending order\n"
" |\n"
" | This is a slice that is sorted in ascending order\n"
" ```\n"
"\n"
" So the produced result will contain these two slices, each one sorted in\n"
" ascending order: `[[1, 2, 3], [0, 1, 2]]`.\n"
"\n"
" - `growing` is an accumulator with the current slice being grown\n"
" - `direction` is the growing direction of the slice being grown, it could\n"
" either be ascending or strictly descending\n"
" - `prev` is the previous element that needs to be added to the growing slice\n"
" it is carried around to check whether we have to keep growing the current\n"
" slice or not\n"
" - `acc` is the accumulator containing the slices sorted in ascending order\n"
).
-spec sequences(
list(AJJ),
fun((AJJ, AJJ) -> gleam@order:order()),
list(AJJ),
sorting(),
AJJ,
list(list(AJJ))
) -> list(list(AJJ)).
sequences(List, Compare, Growing, Direction, Prev, Acc) ->
Growing@1 = [Prev | Growing],
case List of
[] ->
case Direction of
ascending ->
[lists:reverse(Growing@1) | Acc];
descending ->
[Growing@1 | Acc]
end;
[New | Rest] ->
case {Compare(Prev, New), Direction} of
{gt, descending} ->
sequences(Rest, Compare, Growing@1, Direction, New, Acc);
{lt, ascending} ->
sequences(Rest, Compare, Growing@1, Direction, New, Acc);
{eq, ascending} ->
sequences(Rest, Compare, Growing@1, Direction, New, Acc);
{gt, ascending} ->
Acc@1 = case Direction of
ascending ->
[lists:reverse(Growing@1) | Acc];
descending ->
[Growing@1 | Acc]
end,
case Rest of
[] ->
[[New] | Acc@1];
[Next | Rest@1] ->
Direction@1 = case Compare(New, Next) of
lt ->
ascending;
eq ->
ascending;
gt ->
descending
end,
sequences(
Rest@1,
Compare,
[New],
Direction@1,
Next,
Acc@1
)
end;
{lt, descending} ->
Acc@1 = case Direction of
ascending ->
[lists:reverse(Growing@1) | Acc];
descending ->
[Growing@1 | Acc]
end,
case Rest of
[] ->
[[New] | Acc@1];
[Next | Rest@1] ->
Direction@1 = case Compare(New, Next) of
lt ->
ascending;
eq ->
ascending;
gt ->
descending
end,
sequences(
Rest@1,
Compare,
[New],
Direction@1,
Next,
Acc@1
)
end;
{eq, descending} ->
Acc@1 = case Direction of
ascending ->
[lists:reverse(Growing@1) | Acc];
descending ->
[Growing@1 | Acc]
end,
case Rest of
[] ->
[[New] | Acc@1];
[Next | Rest@1] ->
Direction@1 = case Compare(New, Next) of
lt ->
ascending;
eq ->
ascending;
gt ->
descending
end,
sequences(
Rest@1,
Compare,
[New],
Direction@1,
Next,
Acc@1
)
end
end
end.
-file("src/gleam/list.gleam", 1393).
?DOC(
" Merges two lists sorted in ascending order into a single list sorted in\n"
" descending order according to the given comparator function.\n"
"\n"
" This reversing of the sort order is not avoidable if we want to implement\n"
" merge as a tail recursive function. We could reverse the accumulator before\n"
" returning it but that would end up being less efficient; so the merging\n"
" algorithm has to play around this.\n"
).
-spec merge_ascendings(
list(AKG),
list(AKG),
fun((AKG, AKG) -> gleam@order:order()),
list(AKG)
) -> list(AKG).
merge_ascendings(List1, List2, Compare, Acc) ->
case {List1, List2} of
{[], List} ->
reverse_and_prepend(List, Acc);
{List, []} ->
reverse_and_prepend(List, Acc);
{[First1 | Rest1], [First2 | Rest2]} ->
case Compare(First1, First2) of
lt ->
merge_ascendings(Rest1, List2, Compare, [First1 | Acc]);
gt ->
merge_ascendings(List1, Rest2, Compare, [First2 | Acc]);
eq ->
merge_ascendings(List1, Rest2, Compare, [First2 | Acc])
end
end.
-file("src/gleam/list.gleam", 1346).
?DOC(
" Given a list of ascending lists, it merges adjacent pairs into a single\n"
" descending list, halving their number.\n"
" It returns a list of the remaining descending lists.\n"
).
-spec merge_ascending_pairs(
list(list(AJU)),
fun((AJU, AJU) -> gleam@order:order()),
list(list(AJU))
) -> list(list(AJU)).
merge_ascending_pairs(Sequences, Compare, Acc) ->
case Sequences of
[] ->
lists:reverse(Acc);
[Sequence] ->
lists:reverse([lists:reverse(Sequence) | Acc]);
[Ascending1, Ascending2 | Rest] ->
Descending = merge_ascendings(Ascending1, Ascending2, Compare, []),
merge_ascending_pairs(Rest, Compare, [Descending | Acc])
end.
-file("src/gleam/list.gleam", 1420).
?DOC(
" This is exactly the same as merge_ascendings but mirrored: it merges two\n"
" lists sorted in descending order into a single list sorted in ascending\n"
" order according to the given comparator function.\n"
"\n"
" This reversing of the sort order is not avoidable if we want to implement\n"
" merge as a tail recursive function. We could reverse the accumulator before\n"
" returning it but that would end up being less efficient; so the merging\n"
" algorithm has to play around this.\n"
).
-spec merge_descendings(
list(AKL),
list(AKL),
fun((AKL, AKL) -> gleam@order:order()),
list(AKL)
) -> list(AKL).
merge_descendings(List1, List2, Compare, Acc) ->
case {List1, List2} of
{[], List} ->
reverse_and_prepend(List, Acc);
{List, []} ->
reverse_and_prepend(List, Acc);
{[First1 | Rest1], [First2 | Rest2]} ->
case Compare(First1, First2) of
lt ->
merge_descendings(List1, Rest2, Compare, [First2 | Acc]);
gt ->
merge_descendings(Rest1, List2, Compare, [First1 | Acc]);
eq ->
merge_descendings(Rest1, List2, Compare, [First1 | Acc])
end
end.
-file("src/gleam/list.gleam", 1368).
?DOC(" This is the same as merge_ascending_pairs but flipped for descending lists.\n").
-spec merge_descending_pairs(
list(list(AKA)),
fun((AKA, AKA) -> gleam@order:order()),
list(list(AKA))
) -> list(list(AKA)).
merge_descending_pairs(Sequences, Compare, Acc) ->
case Sequences of
[] ->
lists:reverse(Acc);
[Sequence] ->
lists:reverse([lists:reverse(Sequence) | Acc]);
[Descending1, Descending2 | Rest] ->
Ascending = merge_descendings(Descending1, Descending2, Compare, []),
merge_descending_pairs(Rest, Compare, [Ascending | Acc])
end.
-file("src/gleam/list.gleam", 1312).
?DOC(
" Given some some sorted sequences (assumed to be sorted in `direction`) it\n"
" merges them all together until we're left with just a list sorted in\n"
" ascending order.\n"
).
-spec merge_all(
list(list(AJQ)),
sorting(),
fun((AJQ, AJQ) -> gleam@order:order())
) -> list(AJQ).
merge_all(Sequences, Direction, Compare) ->
case {Sequences, Direction} of
{[], _} ->
[];
{[Sequence], ascending} ->
Sequence;
{[Sequence@1], descending} ->
lists:reverse(Sequence@1);
{_, ascending} ->
Sequences@1 = merge_ascending_pairs(Sequences, Compare, []),
merge_all(Sequences@1, descending, Compare);
{_, descending} ->
Sequences@2 = merge_descending_pairs(Sequences, Compare, []),
merge_all(Sequences@2, ascending, Compare)
end.
-file("src/gleam/list.gleam", 1183).
?DOC(
" Sorts from smallest to largest based upon the ordering specified by a given\n"
" function.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" import gleam/int\n"
"\n"
" sort([4, 3, 6, 5, 4, 1, 2], by: int.compare)\n"
" // -> [1, 2, 3, 4, 4, 5, 6]\n"
" ```\n"
).
-spec sort(list(AJG), fun((AJG, AJG) -> gleam@order:order())) -> list(AJG).
sort(List, Compare) ->
case List of
[] ->
[];
[X] ->
[X];
[X@1, Y | Rest] ->
Direction = case Compare(X@1, Y) of
lt ->
ascending;
eq ->
ascending;
gt ->
descending
end,
Sequences = sequences(Rest, Compare, [X@1], Direction, Y, []),
merge_all(Sequences, ascending, Compare)
end.
-file("src/gleam/list.gleam", 1460).
-spec range_loop(integer(), integer(), list(integer())) -> list(integer()).
range_loop(Start, Stop, Acc) ->
case gleam@int:compare(Start, Stop) of
eq ->
[Stop | Acc];
gt ->
range_loop(Start, Stop + 1, [Stop | Acc]);
lt ->
range_loop(Start, Stop - 1, [Stop | Acc])
end.
-file("src/gleam/list.gleam", 1456).
?DOC(
" Creates a list of ints ranging from a given start and finish.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" range(0, 0)\n"
" // -> [0]\n"
" ```\n"
"\n"
" ```gleam\n"
" range(0, 5)\n"
" // -> [0, 1, 2, 3, 4, 5]\n"
" ```\n"
"\n"
" ```gleam\n"
" range(1, -5)\n"
" // -> [1, 0, -1, -2, -3, -4, -5]\n"
" ```\n"
).
-spec range(integer(), integer()) -> list(integer()).
range(Start, Stop) ->
range_loop(Start, Stop, []).
-file("src/gleam/list.gleam", 1486).
-spec repeat_loop(AKV, integer(), list(AKV)) -> list(AKV).
repeat_loop(Item, Times, Acc) ->
case Times =< 0 of
true ->
Acc;
false ->
repeat_loop(Item, Times - 1, [Item | Acc])
end.
-file("src/gleam/list.gleam", 1482).
?DOC(
" Builds a list of a given value a given number of times.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" repeat(\"a\", times: 0)\n"
" // -> []\n"
" ```\n"
"\n"
" ```gleam\n"
" repeat(\"a\", times: 5)\n"
" // -> [\"a\", \"a\", \"a\", \"a\", \"a\"]\n"
" ```\n"
).
-spec repeat(AKT, integer()) -> list(AKT).
repeat(A, Times) ->
repeat_loop(A, Times, []).
-file("src/gleam/list.gleam", 1519).
-spec split_loop(list(ALC), integer(), list(ALC)) -> {list(ALC), list(ALC)}.
split_loop(List, N, Taken) ->
case N =< 0 of
true ->
{lists:reverse(Taken), List};
false ->
case List of
[] ->
{lists:reverse(Taken), []};
[First | Rest] ->
split_loop(Rest, N - 1, [First | Taken])
end
end.
-file("src/gleam/list.gleam", 1515).
?DOC(
" Splits a list in two before the given index.\n"
"\n"
" If the list is not long enough to have the given index the before list will\n"
" be the input list, and the after list will be empty.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" split([6, 7, 8, 9], 0)\n"
" // -> #([], [6, 7, 8, 9])\n"
" ```\n"
"\n"
" ```gleam\n"
" split([6, 7, 8, 9], 2)\n"
" // -> #([6, 7], [8, 9])\n"
" ```\n"
"\n"
" ```gleam\n"
" split([6, 7, 8, 9], 4)\n"
" // -> #([6, 7, 8, 9], [])\n"
" ```\n"
).
-spec split(list(AKY), integer()) -> {list(AKY), list(AKY)}.
split(List, Index) ->
split_loop(List, Index, []).
-file("src/gleam/list.gleam", 1555).
-spec split_while_loop(list(ALL), fun((ALL) -> boolean()), list(ALL)) -> {list(ALL),
list(ALL)}.
split_while_loop(List, F, Acc) ->
case List of
[] ->
{lists:reverse(Acc), []};
[First | Rest] ->
case F(First) of
true ->
split_while_loop(Rest, F, [First | Acc]);
false ->
{lists:reverse(Acc), List}
end
end.
-file("src/gleam/list.gleam", 1548).
?DOC(
" Splits a list in two before the first element that a given function returns\n"
" `False` for.\n"
"\n"
" If the function returns `True` for all elements the first list will be the\n"
" input list, and the second list will be empty.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" split_while([1, 2, 3, 4, 5], fn(x) { x <= 3 })\n"
" // -> #([1, 2, 3], [4, 5])\n"
" ```\n"
"\n"
" ```gleam\n"
" split_while([1, 2, 3, 4, 5], fn(x) { x <= 5 })\n"
" // -> #([1, 2, 3, 4, 5], [])\n"
" ```\n"
).
-spec split_while(list(ALH), fun((ALH) -> boolean())) -> {list(ALH), list(ALH)}.
split_while(List, Predicate) ->
split_while_loop(List, Predicate, []).
-file("src/gleam/list.gleam", 1595).
?DOC(
" Given a list of 2-element tuples, finds the first tuple that has a given\n"
" key as the first element and returns the second element.\n"
"\n"
" If no tuple is found with the given key then `Error(Nil)` is returned.\n"
"\n"
" This function may be useful for interacting with Erlang code where lists of\n"
" tuples are common.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" key_find([#(\"a\", 0), #(\"b\", 1)], \"a\")\n"
" // -> Ok(0)\n"
" ```\n"
"\n"
" ```gleam\n"
" key_find([#(\"a\", 0), #(\"b\", 1)], \"b\")\n"
" // -> Ok(1)\n"
" ```\n"
"\n"
" ```gleam\n"
" key_find([#(\"a\", 0), #(\"b\", 1)], \"c\")\n"
" // -> Error(Nil)\n"
" ```\n"
).
-spec key_find(list({ALQ, ALR}), ALQ) -> {ok, ALR} | {error, nil}.
key_find(Keyword_list, Desired_key) ->
find_map(
Keyword_list,
fun(Keyword) ->
{Key, Value} = Keyword,
case Key =:= Desired_key of
true ->
{ok, Value};
false ->
{error, nil}
end
end
).
-file("src/gleam/list.gleam", 1626).
?DOC(
" Given a list of 2-element tuples, finds all tuples that have a given\n"
" key as the first element and returns the second element.\n"
"\n"
" This function may be useful for interacting with Erlang code where lists of\n"
" tuples are common.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" key_filter([#(\"a\", 0), #(\"b\", 1), #(\"a\", 2)], \"a\")\n"
" // -> [0, 2]\n"
" ```\n"
"\n"
" ```gleam\n"
" key_filter([#(\"a\", 0), #(\"b\", 1)], \"c\")\n"
" // -> []\n"
" ```\n"
).
-spec key_filter(list({ALV, ALW}), ALV) -> list(ALW).
key_filter(Keyword_list, Desired_key) ->
filter_map(
Keyword_list,
fun(Keyword) ->
{Key, Value} = Keyword,
case Key =:= Desired_key of
true ->
{ok, Value};
false ->
{error, nil}
end
end
).
-file("src/gleam/list.gleam", 1666).
-spec key_pop_loop(list({AMF, AMG}), AMF, list({AMF, AMG})) -> {ok,
{AMG, list({AMF, AMG})}} |
{error, nil}.
key_pop_loop(List, Key, Checked) ->
case List of
[] ->
{error, nil};
[{K, V} | Rest] when K =:= Key ->
{ok, {V, reverse_and_prepend(Checked, Rest)}};
[First | Rest@1] ->
key_pop_loop(Rest@1, Key, [First | Checked])
end.
-file("src/gleam/list.gleam", 1662).
?DOC(
" Given a list of 2-element tuples, finds the first tuple that has a given\n"
" key as the first element. This function will return the second element\n"
" of the found tuple and list with tuple removed.\n"
"\n"
" If no tuple is found with the given key then `Error(Nil)` is returned.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" key_pop([#(\"a\", 0), #(\"b\", 1)], \"a\")\n"
" // -> Ok(#(0, [#(\"b\", 1)]))\n"
" ```\n"
"\n"
" ```gleam\n"
" key_pop([#(\"a\", 0), #(\"b\", 1)], \"b\")\n"
" // -> Ok(#(1, [#(\"a\", 0)]))\n"
" ```\n"
"\n"
" ```gleam\n"
" key_pop([#(\"a\", 0), #(\"b\", 1)], \"c\")\n"
" // -> Error(Nil)\n"
" ```\n"
).
-spec key_pop(list({ALZ, AMA}), ALZ) -> {ok, {AMA, list({ALZ, AMA})}} |
{error, nil}.
key_pop(List, Key) ->
key_pop_loop(List, Key, []).
-file("src/gleam/list.gleam", 1700).
-spec key_set_loop(list({AMQ, AMR}), AMQ, AMR, list({AMQ, AMR})) -> list({AMQ,
AMR}).
key_set_loop(List, Key, Value, Inspected) ->
case List of
[{K, _} | Rest] when K =:= Key ->
reverse_and_prepend(Inspected, [{K, Value} | Rest]);
[First | Rest@1] ->
key_set_loop(Rest@1, Key, Value, [First | Inspected]);
[] ->
lists:reverse([{Key, Value} | Inspected])
end.
-file("src/gleam/list.gleam", 1696).
?DOC(
" Given a list of 2-element tuples, inserts a key and value into the list.\n"
"\n"
" If there was already a tuple with the key then it is replaced, otherwise it\n"
" is added to the end of the list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" key_set([#(5, 0), #(4, 1)], 4, 100)\n"
" // -> [#(5, 0), #(4, 100)]\n"
" ```\n"
"\n"
" ```gleam\n"
" key_set([#(5, 0), #(4, 1)], 1, 100)\n"
" // -> [#(5, 0), #(4, 1), #(1, 100)]\n"
" ```\n"
).
-spec key_set(list({AMM, AMN}), AMM, AMN) -> list({AMM, AMN}).
key_set(List, Key, Value) ->
key_set_loop(List, Key, Value, []).
-file("src/gleam/list.gleam", 1728).
?DOC(
" Calls a function for each element in a list, discarding the return value.\n"
"\n"
" Useful for calling a side effect for every item of a list.\n"
"\n"
" ```gleam\n"
" import gleam/io\n"
"\n"
" each([\"1\", \"2\", \"3\"], io.println)\n"
" // -> Nil\n"
" // 1\n"
" // 2\n"
" // 3\n"
" ```\n"
).
-spec each(list(AMV), fun((AMV) -> any())) -> nil.
each(List, F) ->
case List of
[] ->
nil;
[First | Rest] ->
F(First),
each(Rest, F)
end.
-file("src/gleam/list.gleam", 1754).
?DOC(
" Calls a `Result` returning function for each element in a list, discarding\n"
" the return value. If the function returns `Error` then the iteration is\n"
" stopped and the error is returned.\n"
"\n"
" Useful for calling a side effect for every item of a list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" try_each(\n"
" over: [1, 2, 3],\n"
" with: function_that_might_fail,\n"
" )\n"
" // -> Ok(Nil)\n"
" ```\n"
).
-spec try_each(list(AMY), fun((AMY) -> {ok, any()} | {error, ANB})) -> {ok, nil} |
{error, ANB}.
try_each(List, Fun) ->
case List of
[] ->
{ok, nil};
[First | Rest] ->
case Fun(First) of
{ok, _} ->
try_each(Rest, Fun);
{error, E} ->
{error, E}
end
end.
-file("src/gleam/list.gleam", 1787).
-spec partition_loop(list(BFF), fun((BFF) -> boolean()), list(BFF), list(BFF)) -> {list(BFF),
list(BFF)}.
partition_loop(List, Categorise, Trues, Falses) ->
case List of
[] ->
{lists:reverse(Trues), lists:reverse(Falses)};
[First | Rest] ->
case Categorise(First) of
true ->
partition_loop(Rest, Categorise, [First | Trues], Falses);
false ->
partition_loop(Rest, Categorise, Trues, [First | Falses])
end
end.
-file("src/gleam/list.gleam", 1780).
?DOC(
" Partitions a list into a tuple/pair of lists\n"
" by a given categorisation function.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" import gleam/int\n"
"\n"
" [1, 2, 3, 4, 5] |> partition(int.is_odd)\n"
" // -> #([1, 3, 5], [2, 4])\n"
" ```\n"
).
-spec partition(list(ANG), fun((ANG) -> boolean())) -> {list(ANG), list(ANG)}.
partition(List, Categorise) ->
partition_loop(List, Categorise, [], []).
-file("src/gleam/list.gleam", 1807).
?DOC(
" Returns all the permutations of a list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" permutations([1, 2])\n"
" // -> [[1, 2], [2, 1]]\n"
" ```\n"
).
-spec permutations(list(ANP)) -> list(list(ANP)).
permutations(List) ->
case List of
[] ->
[[]];
[_ | _] ->
_pipe@3 = index_map(
List,
fun(I, I_idx) ->
_pipe = index_fold(
List,
[],
fun(Acc, J, J_idx) -> case I_idx =:= J_idx of
true ->
Acc;
false ->
[J | Acc]
end end
),
_pipe@1 = lists:reverse(_pipe),
_pipe@2 = permutations(_pipe@1),
map(_pipe@2, fun(Permutation) -> [I | Permutation] end)
end
),
flatten(_pipe@3)
end.
-file("src/gleam/list.gleam", 1847).
-spec window_loop(list(list(ANX)), list(ANX), integer()) -> list(list(ANX)).
window_loop(Acc, List, N) ->
Window = take(List, N),
case erlang:length(Window) =:= N of
true ->
window_loop([Window | Acc], drop(List, 1), N);
false ->
lists:reverse(Acc)
end.
-file("src/gleam/list.gleam", 1840).
?DOC(
" Returns a list of sliding windows.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" window([1,2,3,4,5], 3)\n"
" // -> [[1, 2, 3], [2, 3, 4], [3, 4, 5]]\n"
" ```\n"
"\n"
" ```gleam\n"
" window([1, 2], 4)\n"
" // -> []\n"
" ```\n"
).
-spec window(list(ANT), integer()) -> list(list(ANT)).
window(List, N) ->
case N =< 0 of
true ->
[];
false ->
window_loop([], List, N)
end.
-file("src/gleam/list.gleam", 1870).
?DOC(
" Returns a list of tuples containing two contiguous elements.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" window_by_2([1,2,3,4])\n"
" // -> [#(1, 2), #(2, 3), #(3, 4)]\n"
" ```\n"
"\n"
" ```gleam\n"
" window_by_2([1])\n"
" // -> []\n"
" ```\n"
).
-spec window_by_2(list(AOD)) -> list({AOD, AOD}).
window_by_2(List) ->
zip(List, drop(List, 1)).
-file("src/gleam/list.gleam", 1883).
?DOC(
" Drops the first elements in a given list for which the predicate function returns `True`.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" drop_while([1, 2, 3, 4], fn (x) { x < 3 })\n"
" // -> [3, 4]\n"
" ```\n"
).
-spec drop_while(list(AOG), fun((AOG) -> boolean())) -> list(AOG).
drop_while(List, Predicate) ->
case List of
[] ->
[];
[First | Rest] ->
case Predicate(First) of
true ->
drop_while(Rest, Predicate);
false ->
[First | Rest]
end
end.
-file("src/gleam/list.gleam", 1913).
-spec take_while_loop(list(AOM), fun((AOM) -> boolean()), list(AOM)) -> list(AOM).
take_while_loop(List, Predicate, Acc) ->
case List of
[] ->
lists:reverse(Acc);
[First | Rest] ->
case Predicate(First) of
true ->
take_while_loop(Rest, Predicate, [First | Acc]);
false ->
lists:reverse(Acc)
end
end.
-file("src/gleam/list.gleam", 1906).
?DOC(
" Takes the first elements in a given list for which the predicate function returns `True`.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" take_while([1, 2, 3, 2, 4], fn (x) { x < 3 })\n"
" // -> [1, 2]\n"
" ```\n"
).
-spec take_while(list(AOJ), fun((AOJ) -> boolean())) -> list(AOJ).
take_while(List, Predicate) ->
take_while_loop(List, Predicate, []).
-file("src/gleam/list.gleam", 1945).
-spec chunk_loop(list(AOV), fun((AOV) -> AOX), AOX, list(AOV), list(list(AOV))) -> list(list(AOV)).
chunk_loop(List, F, Previous_key, Current_chunk, Acc) ->
case List of
[First | Rest] ->
Key = F(First),
case Key =:= Previous_key of
true ->
chunk_loop(Rest, F, Key, [First | Current_chunk], Acc);
false ->
New_acc = [lists:reverse(Current_chunk) | Acc],
chunk_loop(Rest, F, Key, [First], New_acc)
end;
[] ->
lists:reverse([lists:reverse(Current_chunk) | Acc])
end.
-file("src/gleam/list.gleam", 1938).
?DOC(
" Returns a list of chunks in which\n"
" the return value of calling `f` on each element is the same.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" [1, 2, 2, 3, 4, 4, 6, 7, 7] |> chunk(by: fn(n) { n % 2 })\n"
" // -> [[1], [2, 2], [3], [4, 4, 6], [7, 7]]\n"
" ```\n"
).
-spec chunk(list(AOQ), fun((AOQ) -> any())) -> list(list(AOQ)).
chunk(List, F) ->
case List of
[] ->
[];
[First | Rest] ->
chunk_loop(Rest, F, F(First), [First], [])
end.
-file("src/gleam/list.gleam", 1990).
-spec sized_chunk_loop(
list(APH),
integer(),
integer(),
list(APH),
list(list(APH))
) -> list(list(APH)).
sized_chunk_loop(List, Count, Left, Current_chunk, Acc) ->
case List of
[] ->
case Current_chunk of
[] ->
lists:reverse(Acc);
Remaining ->
lists:reverse([lists:reverse(Remaining) | Acc])
end;
[First | Rest] ->
Chunk = [First | Current_chunk],
case Left > 1 of
true ->
sized_chunk_loop(Rest, Count, Left - 1, Chunk, Acc);
false ->
sized_chunk_loop(
Rest,
Count,
Count,
[],
[lists:reverse(Chunk) | Acc]
)
end
end.
-file("src/gleam/list.gleam", 1986).
?DOC(
" Returns a list of chunks containing `count` elements each.\n"
"\n"
" If the last chunk does not have `count` elements, it is instead\n"
" a partial chunk, with less than `count` elements.\n"
"\n"
" For any `count` less than 1 this function behaves as if it was set to 1.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" [1, 2, 3, 4, 5, 6] |> sized_chunk(into: 2)\n"
" // -> [[1, 2], [3, 4], [5, 6]]\n"
" ```\n"
"\n"
" ```gleam\n"
" [1, 2, 3, 4, 5, 6, 7, 8] |> sized_chunk(into: 3)\n"
" // -> [[1, 2, 3], [4, 5, 6], [7, 8]]\n"
" ```\n"
).
-spec sized_chunk(list(APD), integer()) -> list(list(APD)).
sized_chunk(List, Count) ->
sized_chunk_loop(List, Count, Count, [], []).
-file("src/gleam/list.gleam", 2034).
?DOC(
" This function acts similar to fold, but does not take an initial state.\n"
" Instead, it starts from the first element in the list\n"
" and combines it with each subsequent element in turn using the given\n"
" function. The function is called as `fun(accumulator, current_element)`.\n"
"\n"
" Returns `Ok` to indicate a successful run, and `Error` if called on an\n"
" empty list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" [] |> reduce(fn(acc, x) { acc + x })\n"
" // -> Error(Nil)\n"
" ```\n"
"\n"
" ```gleam\n"
" [1, 2, 3, 4, 5] |> reduce(fn(acc, x) { acc + x })\n"
" // -> Ok(15)\n"
" ```\n"
).
-spec reduce(list(APO), fun((APO, APO) -> APO)) -> {ok, APO} | {error, nil}.
reduce(List, Fun) ->
case List of
[] ->
{error, nil};
[First | Rest] ->
{ok, fold(Rest, First, Fun)}
end.
-file("src/gleam/list.gleam", 2058).
-spec scan_loop(list(APW), APY, list(APY), fun((APY, APW) -> APY)) -> list(APY).
scan_loop(List, Accumulator, Accumulated, Fun) ->
case List of
[] ->
lists:reverse(Accumulated);
[First | Rest] ->
Next = Fun(Accumulator, First),
scan_loop(Rest, Next, [Next | Accumulated], Fun)
end.
-file("src/gleam/list.gleam", 2050).
?DOC(
" Similar to `fold`, but yields the state of the accumulator at each stage.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" scan(over: [1, 2, 3], from: 100, with: fn(acc, i) { acc + i })\n"
" // -> [101, 103, 106]\n"
" ```\n"
).
-spec scan(list(APS), APU, fun((APU, APS) -> APU)) -> list(APU).
scan(List, Initial, Fun) ->
scan_loop(List, Initial, [], Fun).
-file("src/gleam/list.gleam", 2091).
?DOC(
" Returns the last element in the given list.\n"
"\n"
" Returns `Error(Nil)` if the list is empty.\n"
"\n"
" This function runs in linear time.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" last([])\n"
" // -> Error(Nil)\n"
" ```\n"
"\n"
" ```gleam\n"
" last([1, 2, 3, 4, 5])\n"
" // -> Ok(5)\n"
" ```\n"
).
-spec last(list(AQB)) -> {ok, AQB} | {error, nil}.
last(List) ->
reduce(List, fun(_, Elem) -> Elem end).
-file("src/gleam/list.gleam", 2109).
?DOC(
" Return unique combinations of elements in the list.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" combinations([1, 2, 3], 2)\n"
" // -> [[1, 2], [1, 3], [2, 3]]\n"
" ```\n"
"\n"
" ```gleam\n"
" combinations([1, 2, 3, 4], 3)\n"
" // -> [[1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4]]\n"
" ```\n"
).
-spec combinations(list(AQF), integer()) -> list(list(AQF)).
combinations(Items, N) ->
case N of
0 ->
[[]];
_ ->
case Items of
[] ->
[];
[First | Rest] ->
First_combinations = begin
_pipe = map(
combinations(Rest, N - 1),
fun(Com) -> [First | Com] end
),
lists:reverse(_pipe)
end,
fold(
First_combinations,
combinations(Rest, N),
fun(Acc, C) -> [C | Acc] end
)
end
end.
-file("src/gleam/list.gleam", 2141).
-spec combination_pairs_loop(list(AQM)) -> list(list({AQM, AQM})).
combination_pairs_loop(Items) ->
case Items of
[] ->
[];
[First | Rest] ->
First_combinations = map(Rest, fun(Other) -> {First, Other} end),
[First_combinations | combination_pairs_loop(Rest)]
end.
-file("src/gleam/list.gleam", 2136).
?DOC(
" Return unique pair combinations of elements in the list\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" combination_pairs([1, 2, 3])\n"
" // -> [#(1, 2), #(1, 3), #(2, 3)]\n"
" ```\n"
).
-spec combination_pairs(list(AQJ)) -> list({AQJ, AQJ}).
combination_pairs(Items) ->
_pipe = combination_pairs_loop(Items),
flatten(_pipe).
-file("src/gleam/list.gleam", 2178).
?DOC(
" Transpose rows and columns of the list of lists.\n"
"\n"
" Notice: This function is not tail recursive,\n"
" and thus may exceed stack size if called,\n"
" with large lists (on target JavaScript).\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" transpose([[1, 2, 3], [101, 102, 103]])\n"
" // -> [[1, 101], [2, 102], [3, 103]]\n"
" ```\n"
).
-spec transpose(list(list(AQU))) -> list(list(AQU)).
transpose(List_of_list) ->
Take_first = fun(List) -> case List of
[] ->
[];
[First] ->
[First];
[First@1 | _] ->
[First@1]
end end,
case List_of_list of
[] ->
[];
[[] | Rest] ->
transpose(Rest);
Rows ->
Firsts = begin
_pipe = Rows,
_pipe@1 = map(_pipe, Take_first),
flatten(_pipe@1)
end,
Rest@1 = transpose(
map(Rows, fun(_capture) -> drop(_capture, 1) end)
),
[Firsts | Rest@1]
end.
-file("src/gleam/list.gleam", 2160).
?DOC(
" Make a list alternating the elements from the given lists\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" interleave([[1, 2], [101, 102], [201, 202]])\n"
" // -> [1, 101, 201, 2, 102, 202]\n"
" ```\n"
).
-spec interleave(list(list(AQQ))) -> list(AQQ).
interleave(List) ->
_pipe = transpose(List),
flatten(_pipe).
-file("src/gleam/list.gleam", 2219).
-spec shuffle_pair_unwrap_loop(list({float(), ARC}), list(ARC)) -> list(ARC).
shuffle_pair_unwrap_loop(List, Acc) ->
case List of
[] ->
Acc;
[Elem_pair | Enumerable] ->
shuffle_pair_unwrap_loop(
Enumerable,
[erlang:element(2, Elem_pair) | Acc]
)
end.
-file("src/gleam/list.gleam", 2227).
-spec do_shuffle_by_pair_indexes(list({float(), ARG})) -> list({float(), ARG}).
do_shuffle_by_pair_indexes(List_of_pairs) ->
sort(
List_of_pairs,
fun(A_pair, B_pair) ->
gleam@float:compare(
erlang:element(1, A_pair),
erlang:element(1, B_pair)
)
end
).
-file("src/gleam/list.gleam", 2212).
?DOC(
" Takes a list, randomly sorts all items and returns the shuffled list.\n"
"\n"
" This function uses `float.random` to decide the order of the elements.\n"
"\n"
" ## Example\n"
"\n"
" ```gleam\n"
" range(1, 10) |> shuffle()\n"
" // -> [1, 6, 9, 10, 3, 8, 4, 2, 7, 5]\n"
" ```\n"
).
-spec shuffle(list(AQZ)) -> list(AQZ).
shuffle(List) ->
_pipe = List,
_pipe@1 = fold(_pipe, [], fun(Acc, A) -> [{rand:uniform(), A} | Acc] end),
_pipe@2 = do_shuffle_by_pair_indexes(_pipe@1),
shuffle_pair_unwrap_loop(_pipe@2, []).
-file("src/gleam/list.gleam", 2249).
?DOC(
" Takes a list and a comparator, and returns the maximum element in the list\n"
"\n"
"\n"
" ## Example\n"
"\n"
" ```gleam\n"
" range(1, 10) |> list.max(int.compare)\n"
" // -> Ok(10)\n"
" ```\n"
"\n"
" ```gleam\n"
" [\"a\", \"c\", \"b\"] |> list.max(string.compare)\n"
" // -> Ok(\"c\")\n"
" ```\n"
).
-spec max(list(ARJ), fun((ARJ, ARJ) -> gleam@order:order())) -> {ok, ARJ} |
{error, nil}.
max(List, Compare) ->
reduce(List, fun(Acc, Other) -> case Compare(Acc, Other) of
gt ->
Acc;
lt ->
Other;
eq ->
Other
end end).
-file("src/gleam/list.gleam", 2320).
-spec log_random() -> float().
log_random() ->
Min_positive = 2.2250738585072014e-308,
_assert_subject = gleam@float:logarithm(rand:uniform() + Min_positive),
{ok, Random} = case _assert_subject of
{ok, _} -> _assert_subject;
_assert_fail ->
erlang:error(#{gleam_error => let_assert,
message => <<"Pattern match failed, no pattern matched the value."/utf8>>,
value => _assert_fail,
module => <<"gleam/list"/utf8>>,
function => <<"log_random"/utf8>>,
line => 2322})
end,
Random.
-file("src/gleam/list.gleam", 2296).
-spec sample_loop(
list(ARR),
gleam@dict:dict(integer(), ARR),
integer(),
integer(),
float()
) -> gleam@dict:dict(integer(), ARR).
sample_loop(List, Reservoir, K, Index, W) ->
Skip = begin
_assert_subject = gleam@float:logarithm(1.0 - W),
{ok, Log_result} = case _assert_subject of
{ok, _} -> _assert_subject;
_assert_fail ->
erlang:error(#{gleam_error => let_assert,
message => <<"Pattern match failed, no pattern matched the value."/utf8>>,
value => _assert_fail,
module => <<"gleam/list"/utf8>>,
function => <<"sample_loop"/utf8>>,
line => 2304})
end,
_pipe = case Log_result of
+0.0 -> +0.0;
-0.0 -> -0.0;
Gleam@denominator -> log_random() / Gleam@denominator
end,
_pipe@1 = math:floor(_pipe),
erlang:round(_pipe@1)
end,
Index@1 = (Index + Skip) + 1,
case drop(List, Skip) of
[] ->
Reservoir;
[First | Rest] ->
Reservoir@1 = gleam@dict:insert(
Reservoir,
gleam@int:random(K),
First
),
W@1 = W * math:exp(case erlang:float(K) of
+0.0 -> +0.0;
-0.0 -> -0.0;
Gleam@denominator@1 -> log_random() / Gleam@denominator@1
end),
sample_loop(Rest, Reservoir@1, K, Index@1, W@1)
end.
-file("src/gleam/list.gleam", 2273).
?DOC(
" Take a random sample of k elements from a list using reservoir sampling via\n"
" Algo L. Returns an empty list if the sample size is less than or equal to 0.\n"
"\n"
" Order is not random, only selection is.\n"
"\n"
" ## Examples\n"
"\n"
" ```gleam\n"
" reservoir_sample([1, 2, 3, 4, 5], 3)\n"
" // -> [2, 4, 5] // A random sample of 3 items\n"
" ```\n"
).
-spec sample(list(ARN), integer()) -> list(ARN).
sample(List, K) ->
case K =< 0 of
true ->
[];
false ->
{Reservoir, List@1} = split(List, K),
case erlang:length(Reservoir) < K of
true ->
Reservoir;
false ->
Reservoir@1 = begin
_pipe = Reservoir,
_pipe@1 = map2(
range(0, K - 1),
_pipe,
fun(A, B) -> {A, B} end
),
maps:from_list(_pipe@1)
end,
W = math:exp(case erlang:float(K) of
+0.0 -> +0.0;
-0.0 -> -0.0;
Gleam@denominator -> log_random() / Gleam@denominator
end),
_pipe@2 = sample_loop(List@1, Reservoir@1, K, K, W),
maps:values(_pipe@2)
end
end.