@spec ascii_printable?(list(), 0) :: true

@spec ascii_printable?([], limit) :: true when limit: :infinity |pos_integer()

@spec ascii_printable?([...], limit) ::boolean()when limit: :infinity |pos_integer()

Checks iflist is a charlist made only of printable ASCII characters.

Takes an optionallimit as a second argument.ascii_printable?/2 onlychecks the printability of the list up to thelimit.

A printable charlist in Elixir contains only the printable characters in thestandard seven-bit ASCII character encoding, which are characters ranging from32 to 126 in decimal notation, plus the following control characters:

• ?\a - Bell
• ?\b - Backspace
• ?\t - Horizontal tab
• ?\n - Line feed
• ?\v - Vertical tab
• ?\f - Form feed
• ?\r - Carriage return
• ?\e - Escape

For more information read theCharacter groupssection in the Wikipedia article of theASCII standard.

Examples

iex>List.ascii_printable?(~c"abc")trueiex>List.ascii_printable?(~c"abc"++[0])falseiex>List.ascii_printable?(~c"abc"++[0],2)true

Improper lists are not printable, even if made only of ASCII characters:

iex>List.ascii_printable?(~c"abc"++?d)false

@spec delete([],any()) :: []

@spec delete([...],any()) ::list()

Deletes the givenelement from thelist. Returns a new list withoutthe element.

If theelement occurs more than once in thelist, justthe first occurrence is removed.

Examples

iex>List.delete([:a,:b,:c],:a)[:b,:c]iex>List.delete([:a,:b,:c],:d)[:a,:b,:c]iex>List.delete([:a,:b,:b,:c],:b)[:a,:b,:c]iex>List.delete([],:b)[]

@spec delete_at(list(),integer()) ::list()

Produces a new list by removing the value at the specifiedindex.

Negative indices indicate an offset from the end of thelist.Ifindex is out of bounds, the originallist is returned.

Examples

iex>List.delete_at([1,2,3],0)[2,3]iex>List.delete_at([1,2,3],10)[1,2,3]iex>List.delete_at([1,2,3],-1)[1,2]

@spec duplicate(any(), 0) :: []

@spec duplicate(elem,pos_integer()) :: [elem, ...] when elem: var

Duplicates the given elementn times in a list.

n is an integer greater than or equal to0.

Ifn is0, an empty list is returned.

Examples

iex>List.duplicate("hello",0)[]iex>List.duplicate("hi",1)["hi"]iex>List.duplicate("bye",2)["bye","bye"]iex>List.duplicate([1,2],3)[[1,2],[1,2],[1,2]]

@spec ends_with?([...], [...]) ::boolean()

@spec ends_with?(list(), []) :: true

@spec ends_with?([], [...]) :: false

Returnstrue iflist ends with the givensuffix list, otherwise returnsfalse.

Ifsuffix is an empty list, it returnstrue.

Examples

iex>List.ends_with?([1,2,3],[2,3])trueiex>List.ends_with?([1,2],[1,2,3])falseiex>List.ends_with?([:alpha],[])trueiex>List.ends_with?([],[:alpha])false

@spec first([],any()) ::any()

@spec first([elem, ...],any()) :: elem when elem: var

Returns the first element inlist ordefault iflist is empty.

first/2 has been introduced in Elixir v1.12.0, whilefirst/1 has been available since v1.0.0.

Examples

iex>List.first([])niliex>List.first([],1)1iex>List.first([1])1iex>List.first([1,2,3])1

@spec flatten(deep_list) ::list() when deep_list: [any() | deep_list]

Flattens the givenlist of nested lists.

Empty list elements are discarded.

Examples

iex>List.flatten([1,[[2],3]])[1,2,3]iex>List.flatten([[],[[],[]]])[]

@spec flatten(deep_list, [elem]) :: [elem]when deep_list: [elem | deep_list], elem: var

Flattens the givenlist of nested lists.The listtail will be added at the end ofthe flattened list.

Empty list elements fromlist are discarded,but not the ones fromtail.

Examples

iex>List.flatten([1,[[2],3]],[4,5])[1,2,3,4,5]iex>List.flatten([1,[],2],[3,[],4])[1,2,3,[],4]

@spec foldl([elem], acc, (elem, acc -> acc)) :: acc when elem: var, acc: var

Folds (reduces) the given list from the left witha function. Requires an accumulator, which can be any value.

Examples

iex>List.foldl([5,5],10,fnx,acc->x+accend)20iex>List.foldl([1,2,3,4],0,fnx,acc->x-accend)2iex>List.foldl([1,2,3],{0,0},fnx,{a1,a2}->{a1+x,a2-x}end){6,-6}

@spec foldr([elem], acc, (elem, acc -> acc)) :: acc when elem: var, acc: var

Folds (reduces) the given list from the right witha function. Requires an accumulator, which can be any value.

Examples

iex>List.foldr([1,2,3,4],0,fnx,acc->x-accend)-2iex>List.foldr([1,2,3,4],%{sum:0,product:1},fnx,%{sum:a1,product:a2}->%{sum:a1+x,product:a2*x}end)%{product:24,sum:10}

@spec improper?(maybe_improper_list()) ::boolean()

Returnstrue iflist is an improper list. Otherwise returnsfalse.

Examples

iex>List.improper?([1,2|3])trueiex>List.improper?([1,2,3])false

@spec insert_at(list(),integer(),any()) ::list()

Returns a list withvalue inserted at the specifiedindex.

Note thatindex is capped at the list length. Negative indicesindicate an offset from the end of thelist.

Examples

iex>List.insert_at([1,2,3,4],2,0)[1,2,0,3,4]iex>List.insert_at([1,2,3],10,0)[1,2,3,0]iex>List.insert_at([1,2,3],-1,0)[1,2,3,0]iex>List.insert_at([1,2,3],-10,0)[0,1,2,3]

@spec keydelete([tuple()],any(),non_neg_integer()) :: [tuple()]

Receives alist of tuples and deletes the first tuplewhere the element atposition matches thegivenkey. Returns the new list.

Examples

iex>List.keydelete([a:1,b:2],:a,0)[b:2]iex>List.keydelete([a:1,b:2],2,1)[a:1]iex>List.keydelete([a:1,b:2],:c,0)[a:1,b:2]

This function works for any list of tuples:

iex>List.keydelete([{22,"SSH"},{80,"HTTP"}],80,0)[{22,"SSH"}]

@spec keyfind([tuple()],any(),non_neg_integer(),any()) ::any()

Receives a list of tuples and returns the first tuplewhere the element atposition in the tuple matches thegivenkey.

If no matching tuple is found,default is returned.

Examples

iex>List.keyfind([a:1,b:2],:a,0){:a,1}iex>List.keyfind([a:1,b:2],2,1){:b,2}iex>List.keyfind([a:1,b:2],:c,0)nil

This function works for any list of tuples:

iex>List.keyfind([{22,"SSH"},{80,"HTTP"}],22,0){22,"SSH"}

@spec keyfind!([tuple()],any(),non_neg_integer()) ::any()

Receives a list of tuples and returns the first tuplewhere the element atposition in the tuple matches thegivenkey.

If no matching tuple is found, an error is raised.

Examples

iex>List.keyfind!([a:1,b:2],:a,0){:a,1}iex>List.keyfind!([a:1,b:2],2,1){:b,2}iex>List.keyfind!([a:1,b:2],:c,0)** (KeyError) key :c at position 0 not found in: [a: 1, b: 2]

This function works for any list of tuples:

iex>List.keyfind!([{22,"SSH"},{80,"HTTP"}],22,0){22,"SSH"}

@spec keymember?([tuple()],any(),non_neg_integer()) ::boolean()

Receives a list of tuples and returnstrue if there isa tuple where the element atposition in the tuple matchesthe givenkey.

Examples

iex>List.keymember?([a:1,b:2],:a,0)trueiex>List.keymember?([a:1,b:2],2,1)trueiex>List.keymember?([a:1,b:2],:c,0)false

This function works for any list of tuples:

iex>List.keymember?([{22,"SSH"},{80,"HTTP"}],22,0)true

@spec keyreplace([tuple()],any(),non_neg_integer(),tuple()) :: [tuple()]

Receives a list of tuples and if the identified element bykey atpositionexists, it is replaced withnew_tuple.

Examples

iex>List.keyreplace([a:1,b:2],:a,0,{:a,3})[a:3,b:2]iex>List.keyreplace([a:1,b:2],:a,1,{:a,3})[a:1,b:2]

This function works for any list of tuples:

iex>List.keyreplace([{22,"SSH"},{80,"HTTP"}],22,0,{22,"Secure Shell"})[{22,"Secure Shell"},{80,"HTTP"}]

@spec keysort(  [tuple()],non_neg_integer(),  (any(),any() ->boolean())  | :asc  | :desc  |module()  | {:asc | :desc,module()}) :: [tuple()]

Receives a list of tuples and sorts the elementsatposition of the tuples.

The sort is stable.

Asorter argument is available since Elixir v1.14.0. Similar toEnum.sort/2, the sorter can be an anonymous function, the atoms:asc or:desc, or module that implements a compare function.

Examples

iex>List.keysort([a:5,b:1,c:3],1)[b:1,c:3,a:5]iex>List.keysort([a:5,c:1,b:3],0)[a:5,b:3,c:1]

To sort in descending order:

iex>List.keysort([a:5,c:1,b:3],0,:desc)[c:1,b:3,a:5]

As inEnum.sort/2, avoid using the default sorting function to sortstructs, as by default it performs structural comparison instead of asemantic one. In such cases, you shall pass a sorting function as thirdelement or any module that implements acompare/2 function. For example,if you have tuples with user names and their birthday, and you want tosort on their birthday, in both ascending and descending order, you shoulddo:

iex>users=[...>{"Ellis",~D[1943-05-11]},...>{"Lovelace",~D[1815-12-10]},...>{"Turing",~D[1912-06-23]}...>]iex>List.keysort(users,1,Date)[{"Lovelace",~D[1815-12-10]},{"Turing",~D[1912-06-23]},{"Ellis",~D[1943-05-11]}]iex>List.keysort(users,1,{:desc,Date})[{"Ellis",~D[1943-05-11]},{"Turing",~D[1912-06-23]},{"Lovelace",~D[1815-12-10]}]

@spec keystore([tuple()],any(),non_neg_integer(),tuple()) :: [tuple(), ...]

Receives alist of tuples and replaces the elementidentified bykey atposition withnew_tuple.

If the element does not exist, it is added to the end of thelist.

Examples

iex>List.keystore([a:1,b:2],:a,0,{:a,3})[a:3,b:2]iex>List.keystore([a:1,b:2],:c,0,{:c,3})[a:1,b:2,c:3]

This function works for any list of tuples:

iex>List.keystore([{22,"SSH"}],80,0,{80,"HTTP"})[{22,"SSH"},{80,"HTTP"}]

@spec keytake([tuple()],any(),non_neg_integer()) :: {tuple(), [tuple()]} | nil

Receives alist of tuples and returns the first tuplewhere the element atposition in the tuple matches thegivenkey, as well as thelist without found tuple.

If such a tuple is not found,nil will be returned.

Examples

iex>List.keytake([a:1,b:2],:a,0){{:a,1},[b:2]}iex>List.keytake([a:1,b:2],2,1){{:b,2},[a:1]}iex>List.keytake([a:1,b:2],:c,0)nil

This function works for any list of tuples:

iex>List.keytake([{22,"SSH"},{80,"HTTP"}],80,0){{80,"HTTP"},[{22,"SSH"}]}

@spec last([],any()) ::any()

@spec last([elem, ...],any()) :: elem when elem: var

Returns the last element inlist ordefault iflist is empty.

last/2 has been introduced in Elixir v1.12.0, whilelast/1 has been available since v1.0.0.

Examples

iex>List.last([])niliex>List.last([],1)1iex>List.last([1])1iex>List.last([1,2,3])3

@spec myers_difference(list(),list()) :: [{:eq | :ins | :del,list()}]

Returns a keyword list that represents anedit script.

The algorithm is outlined in the"An O(ND) Difference Algorithm and Its Variations" paper by E. Myers.

Anedit script is a keyword list. Each key describes the "editing action" totake in order to bringlist1 closer to being equal tolist2; a key can be:eq,:ins, or:del. Each value is a sublist of eitherlist1 orlist2that should be inserted (if the corresponding key is:ins), deleted (if thecorresponding key is:del), or left alone (if the corresponding key is:eq) inlist1 in order to be closer tolist2.

Seemyers_difference/3 if you want to handle nesting in the diff scripts.

Examples

iex>List.myers_difference([1,4,2,3],[1,2,3,4])[eq:[1],del:[4],eq:[2,3],ins:[4]]

@spec myers_difference(list(),list(), (term(),term() -> script | nil)) :: scriptwhen script: [{:eq | :ins | :del | :diff,list()}]

Returns a keyword list that represents anedit script with nested diffs.

This is an extension ofmyers_difference/2 where adiff_script functioncan be given in case it is desired to compute nested differences. The functionmay return a list with the inner edit script ornil in case there is nosuch script. The returned inner edit script will be under the:diff key.

Examples

iex>List.myers_difference(["a","db","c"],["a","bc"],&String.myers_difference/2)[eq:["a"],diff:[del:"d",eq:"b",ins:"c"],del:["c"]]

@spec pop_at(list(),integer(),any()) :: {any(),list()}

Returns and removes the value at the specifiedindex in thelist.

Negative indices indicate an offset from the end of thelist.Ifindex is out of bounds, the originallist is returned.

Examples

iex>List.pop_at([1,2,3],0){1,[2,3]}iex>List.pop_at([1,2,3],5){nil,[1,2,3]}iex>List.pop_at([1,2,3],5,10){10,[1,2,3]}iex>List.pop_at([1,2,3],-1){3,[1,2]}

@spec replace_at(list(),integer(),any()) ::list()

Returns a list with a replaced value at the specifiedindex.

Negative indices indicate an offset from the end of thelist.Ifindex is out of bounds, the originallist is returned.

Examples

iex>List.replace_at([1,2,3],0,0)[0,2,3]iex>List.replace_at([1,2,3],10,0)[1,2,3]iex>List.replace_at([1,2,3],-1,0)[1,2,0]iex>List.replace_at([1,2,3],-10,0)[1,2,3]

@spec starts_with?([...], [...]) ::boolean()

@spec starts_with?(list(), []) :: true

@spec starts_with?([], [...]) :: false

Returnstrue iflist starts with the givenprefix list, otherwise returnsfalse.

Ifprefix is an empty list, it returnstrue.

Examples

iex>List.starts_with?([1,2,3],[1,2])trueiex>List.starts_with?([1,2],[1,2,3])falseiex>List.starts_with?([:alpha],[])trueiex>List.starts_with?([],[:alpha])false

@spec to_atom(charlist()) ::atom()

Converts a charlist to an atom.

Elixir supports conversions from charlists which contain any Unicodecode point.

Inlined by the compiler.

Examples

iex>List.to_atom(~c"Elixir"):Elixiriex>List.to_atom(~c"🌢 Elixir"):"🌢 Elixir"

@spec to_charlist(:unicode.charlist()) ::charlist()

Converts a list of integers representing Unicode code points, lists orstrings into a charlist.

Note that this function expects a list of integers representingUnicode code points. If you have a list of bytes, you must instead usethe:binary module.

Examples

iex>~c"æß"=List.to_charlist([0x00E6,0x00DF])[230,223]iex>List.to_charlist([0x0061,"bc"])~c"abc"iex>List.to_charlist([0x0064,"ee",[~c"p"]])~c"deep"

@spec to_existing_atom(charlist()) ::atom()

Converts a charlist to an existing atom.

Elixir supports conversions from charlists which contain any Unicodecode point. Raises anArgumentError if the atom does not exist.

Inlined by the compiler.

Examples

iex>_=:my_atomiex>List.to_existing_atom(~c"my_atom"):my_atomiex>_=:"🌢 Elixir"iex>List.to_existing_atom(~c"🌢 Elixir"):"🌢 Elixir"

@spec to_float(charlist()) ::float()

Returns the float whose text representation ischarlist.

Inlined by the compiler.

Examples

iex>List.to_float(~c"2.2017764e+0")2.2017764

@spec to_integer(charlist()) ::integer()

Returns an integer whose text representation ischarlist.

Inlined by the compiler.

Examples

iex>List.to_integer(~c"123")123

@spec to_integer(charlist(),  2..36) ::integer()

Returns an integer whose text representation ischarlist in basebase.

Inlined by the compiler.

The base needs to be between2 and36.

Examples

iex>List.to_integer(~c"3FF",16)1023

@spec to_string(:unicode.charlist()) ::String.t()

Converts a list of integers representing code points, lists orstrings into a string.

To be converted to a string, a list must either be empty or onlycontain the following elements:

• strings
• integers representing Unicode code points
• a list containing one of these three elements

Note that this function expects a list of integers representingUnicode code points. If you have a list of bytes, you must instead usethe:binary module.

Examples

iex>List.to_string([0x00E6,0x00DF])"æß"iex>List.to_string([0x0061,"bc"])"abc"iex>List.to_string([0x0064,"ee",[~c"p"]])"deep"iex>List.to_string([])""

@spec to_tuple(list()) ::tuple()

Converts a list to a tuple.

Inlined by the compiler.

Examples

iex>List.to_tuple([:share,[:elixir,163]]){:share,[:elixir,163]}

@spec update_at([elem],integer(), (elem ->any())) ::list() when elem: var

Returns a list with an updated value at the specifiedindex.

Negative indices indicate an offset from the end of thelist.Ifindex is out of bounds, the originallist is returned.

Examples

iex>List.update_at([1,2,3],0,&(&1+10))[11,2,3]iex>List.update_at([1,2,3],10,&(&1+10))[1,2,3]iex>List.update_at([1,2,3],-1,&(&1+10))[1,2,13]iex>List.update_at([1,2,3],-10,&(&1+10))[1,2,3]

@spec wrap(term()) ::maybe_improper_list()

Wrapsterm in a list if this is not list.

Ifterm is already a list, it returns the list.Ifterm isnil, it returns an empty list.

Examples

iex>List.wrap("hello")["hello"]iex>List.wrap([1,2,3])[1,2,3]iex>List.wrap(nil)[]