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NAME
lists - List Processing Functions
DESCRIPTION
This module contains functions for list processing.
Unless otherwise stated, all functions assume that position numbering starts at 1. That is, the first
element of a list is at position 1.
Two terms T1 and T2 compare equal if T1 == T2 evaluates to true. They match if T1 =:= T2 evaluates to
true.
Whenever an ordering function F is expected as argument, it is assumed that the following properties hold
of F for all x, y and z:
* if x F y and y F x then x = y (F is antisymmetric);
* if x F y and y F z then x F z (F is transitive);
* x F y or y F x (F is total).
An example of a typical ordering function is less than or equal to, =</2.
EXPORTS
all(Pred, List) -> boolean()
Types:
Pred = fun((Elem :: T) -> boolean())
List = [T]
T = term()
Returns true if Pred(Elem) returns true for all elements Elem in List, otherwise false.
any(Pred, List) -> boolean()
Types:
Pred = fun((Elem :: T) -> boolean())
List = [T]
T = term()
Returns true if Pred(Elem) returns true for at least one element Elem in List.
append(ListOfLists) -> List1
Types:
ListOfLists = [List]
List = List1 = [T]
T = term()
Returns a list in which all the sub-lists of ListOfLists have been appended. For example:
> lists:append([[1, 2, 3], [a, b], [4, 5, 6]]).
[1,2,3,a,b,4,5,6]
append(List1, List2) -> List3
Types:
List1 = List2 = List3 = [T]
T = term()
Returns a new list List3 which is made from the elements of List1 followed by the elements of
List2. For example:
> lists:append("abc", "def").
"abcdef"
lists:append(A, B) is equivalent to A ++ B.
concat(Things) -> string()
Types:
Things = [Thing]
Thing = atom() | integer() | float() | string()
Concatenates the text representation of the elements of Things. The elements of Things can be
atoms, integers, floats or strings.
> lists:concat([doc, '/', file, '.', 3]).
"doc/file.3"
delete(Elem, List1) -> List2
Types:
Elem = T
List1 = List2 = [T]
T = term()
Returns a copy of List1 where the first element matching Elem is deleted, if there is such an
element.
dropwhile(Pred, List1) -> List2
Types:
Pred = fun((Elem :: T) -> boolean())
List1 = List2 = [T]
T = term()
Drops elements Elem from List1 while Pred(Elem) returns true and returns the remaining list.
duplicate(N, Elem) -> List
Types:
N = integer() >= 0
Elem = T
List = [T]
T = term()
Returns a list which contains N copies of the term Elem. For example:
> lists:duplicate(5, xx).
[xx,xx,xx,xx,xx]
filter(Pred, List1) -> List2
Types:
Pred = fun((Elem :: T) -> boolean())
List1 = List2 = [T]
T = term()
List2 is a list of all elements Elem in List1 for which Pred(Elem) returns true.
filtermap(Fun, List1) -> List2
Types:
Fun = fun((Elem) -> boolean() | {true, Value})
List1 = [Elem]
List2 = [Elem | Value]
Elem = Value = term()
Calls Fun(Elem) on successive elements Elem of List1. Fun/2 must return either a boolean or a
tuple {true, Value}. The function returns the list of elements for which Fun returns a new value,
where a value of true is synonymous with {true, Elem}.
That is, filtermap behaves as if it had been defined as follows:
filtermap(Fun, List1) ->
lists:foldr(fun(Elem, Acc) ->
case Fun(Elem) of
false -> Acc;
true -> [Elem|Acc];
{true,Value} -> [Value|Acc]
end,
end, [], List1).
Example:
> lists:filtermap(fun(X) -> case X rem 2 of 0 -> {true, X div 2}; _ -> false end end, [1,2,3,4,5]).
[1,2]
flatlength(DeepList) -> integer() >= 0
Types:
DeepList = [term() | DeepList]
Equivalent to length(flatten(DeepList)), but more efficient.
flatmap(Fun, List1) -> List2
Types:
Fun = fun((A) -> [B])
List1 = [A]
List2 = [B]
A = B = term()
Takes a function from As to lists of Bs, and a list of As (List1) and produces a list of Bs by
applying the function to every element in List1 and appending the resulting lists.
That is, flatmap behaves as if it had been defined as follows:
flatmap(Fun, List1) ->
append(map(Fun, List1)).
Example:
> lists:flatmap(fun(X)->[X,X] end, [a,b,c]).
[a,a,b,b,c,c]
flatten(DeepList) -> List
Types:
DeepList = [term() | DeepList]
List = [term()]
Returns a flattened version of DeepList.
flatten(DeepList, Tail) -> List
Types:
DeepList = [term() | DeepList]
Tail = List = [term()]
Returns a flattened version of DeepList with the tail Tail appended.
foldl(Fun, Acc0, List) -> Acc1
Types:
Fun = fun((Elem :: T, AccIn) -> AccOut)
Acc0 = Acc1 = AccIn = AccOut = term()
List = [T]
T = term()
Calls Fun(Elem, AccIn) on successive elements A of List, starting with AccIn == Acc0. Fun/2 must
return a new accumulator which is passed to the next call. The function returns the final value of
the accumulator. Acc0 is returned if the list is empty. For example:
> lists:foldl(fun(X, Sum) -> X + Sum end, 0, [1,2,3,4,5]).
15
> lists:foldl(fun(X, Prod) -> X * Prod end, 1, [1,2,3,4,5]).
120
foldr(Fun, Acc0, List) -> Acc1
Types:
Fun = fun((Elem :: T, AccIn) -> AccOut)
Acc0 = Acc1 = AccIn = AccOut = term()
List = [T]
T = term()
Like foldl/3, but the list is traversed from right to left. For example:
> P = fun(A, AccIn) -> io:format("~p ", [A]), AccIn end.
#Fun<erl_eval.12.2225172>
> lists:foldl(P, void, [1,2,3]).
1 2 3 void
> lists:foldr(P, void, [1,2,3]).
3 2 1 void
foldl/3 is tail recursive and would usually be preferred to foldr/3.
foreach(Fun, List) -> ok
Types:
Fun = fun((Elem :: T) -> term())
List = [T]
T = term()
Calls Fun(Elem) for each element Elem in List. This function is used for its side effects and the
evaluation order is defined to be the same as the order of the elements in the list.
keydelete(Key, N, TupleList1) -> TupleList2
Types:
Key = term()
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = TupleList2 = [Tuple]
Tuple = tuple()
Returns a copy of TupleList1 where the first occurrence of a tuple whose Nth element compares
equal to Key is deleted, if there is such a tuple.
keyfind(Key, N, TupleList) -> Tuple | false
Types:
Key = term()
N = integer() >= 1
1..tuple_size(Tuple)
TupleList = [Tuple]
Tuple = tuple()
Searches the list of tuples TupleList for a tuple whose Nth element compares equal to Key. Returns
Tuple if such a tuple is found, otherwise false.
keymap(Fun, N, TupleList1) -> TupleList2
Types:
Fun = fun((Term1 :: term()) -> Term2 :: term())
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = TupleList2 = [Tuple]
Tuple = tuple()
Returns a list of tuples where, for each tuple in TupleList1, the Nth element Term1 of the tuple
has been replaced with the result of calling Fun(Term1).
Examples:
> Fun = fun(Atom) -> atom_to_list(Atom) end.
#Fun<erl_eval.6.10732646>
2> lists:keymap(Fun, 2, [{name,jane,22},{name,lizzie,20},{name,lydia,15}]).
[{name,"jane",22},{name,"lizzie",20},{name,"lydia",15}]
keymember(Key, N, TupleList) -> boolean()
Types:
Key = term()
N = integer() >= 1
1..tuple_size(Tuple)
TupleList = [Tuple]
Tuple = tuple()
Returns true if there is a tuple in TupleList whose Nth element compares equal to Key, otherwise
false.
keymerge(N, TupleList1, TupleList2) -> TupleList3
Types:
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = [T1]
TupleList2 = [T2]
TupleList3 = [(T1 | T2)]
T1 = T2 = Tuple
Tuple = tuple()
Returns the sorted list formed by merging TupleList1 and TupleList2. The merge is performed on the
Nth element of each tuple. Both TupleList1 and TupleList2 must be key-sorted prior to evaluating
this function. When two tuples compare equal, the tuple from TupleList1 is picked before the tuple
from TupleList2.
keyreplace(Key, N, TupleList1, NewTuple) -> TupleList2
Types:
Key = term()
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = TupleList2 = [Tuple]
NewTuple = Tuple
Tuple = tuple()
Returns a copy of TupleList1 where the first occurrence of a T tuple whose Nth element compares
equal to Key is replaced with NewTuple, if there is such a tuple T.
keysearch(Key, N, TupleList) -> {value, Tuple} | false
Types:
Key = term()
N = integer() >= 1
1..tuple_size(Tuple)
TupleList = [Tuple]
Tuple = tuple()
Searches the list of tuples TupleList for a tuple whose Nth element compares equal to Key. Returns
{value, Tuple} if such a tuple is found, otherwise false.
Note:
This function is retained for backward compatibility. The function lists:keyfind/3 (introduced in
R13A) is in most cases more convenient.
keysort(N, TupleList1) -> TupleList2
Types:
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = TupleList2 = [Tuple]
Tuple = tuple()
Returns a list containing the sorted elements of the list TupleList1. Sorting is performed on the
Nth element of the tuples. The sort is stable.
keystore(Key, N, TupleList1, NewTuple) -> TupleList2
Types:
Key = term()
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = [Tuple]
TupleList2 = [Tuple, ...]
NewTuple = Tuple
Tuple = tuple()
Returns a copy of TupleList1 where the first occurrence of a tuple T whose Nth element compares
equal to Key is replaced with NewTuple, if there is such a tuple T. If there is no such tuple T a
copy of TupleList1 where [NewTuple] has been appended to the end is returned.
keytake(Key, N, TupleList1) -> {value, Tuple, TupleList2} | false
Types:
Key = term()
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = TupleList2 = [tuple()]
Tuple = tuple()
Searches the list of tuples TupleList1 for a tuple whose Nth element compares equal to Key.
Returns {value, Tuple, TupleList2} if such a tuple is found, otherwise false. TupleList2 is a copy
of TupleList1 where the first occurrence of Tuple has been removed.
last(List) -> Last
Types:
List = [T, ...]
Last = T
T = term()
Returns the last element in List.
map(Fun, List1) -> List2
Types:
Fun = fun((A) -> B)
List1 = [A]
List2 = [B]
A = B = term()
Takes a function from As to Bs, and a list of As and produces a list of Bs by applying the
function to every element in the list. This function is used to obtain the return values. The
evaluation order is implementation dependent.
mapfoldl(Fun, Acc0, List1) -> {List2, Acc1}
Types:
Fun = fun((A, AccIn) -> {B, AccOut})
Acc0 = Acc1 = AccIn = AccOut = term()
List1 = [A]
List2 = [B]
A = B = term()
mapfoldl combines the operations of map/2 and foldl/3 into one pass. An example, summing the
elements in a list and double them at the same time:
> lists:mapfoldl(fun(X, Sum) -> {2*X, X+Sum} end,
0, [1,2,3,4,5]).
{[2,4,6,8,10],15}
mapfoldr(Fun, Acc0, List1) -> {List2, Acc1}
Types:
Fun = fun((A, AccIn) -> {B, AccOut})
Acc0 = Acc1 = AccIn = AccOut = term()
List1 = [A]
List2 = [B]
A = B = term()
mapfoldr combines the operations of map/2 and foldr/3 into one pass.
max(List) -> Max
Types:
List = [T, ...]
Max = T
T = term()
Returns the first element of List that compares greater than or equal to all other elements of
List.
member(Elem, List) -> boolean()
Types:
Elem = T
List = [T]
T = term()
Returns true if Elem matches some element of List, otherwise false.
merge(ListOfLists) -> List1
Types:
ListOfLists = [List]
List = List1 = [T]
T = term()
Returns the sorted list formed by merging all the sub-lists of ListOfLists. All sub-lists must be
sorted prior to evaluating this function. When two elements compare equal, the element from the
sub-list with the lowest position in ListOfLists is picked before the other element.
merge(List1, List2) -> List3
Types:
List1 = [X]
List2 = [Y]
List3 = [(X | Y)]
X = Y = term()
Returns the sorted list formed by merging List1 and List2. Both List1 and List2 must be sorted
prior to evaluating this function. When two elements compare equal, the element from List1 is
picked before the element from List2.
merge(Fun, List1, List2) -> List3
Types:
Fun = fun((A, B) -> boolean())
List1 = [A]
List2 = [B]
List3 = [(A | B)]
A = B = term()
Returns the sorted list formed by merging List1 and List2. Both List1 and List2 must be sorted
according to the ordering function Fun prior to evaluating this function. Fun(A, B) should return
true if A compares less than or equal to B in the ordering, false otherwise. When two elements
compare equal, the element from List1 is picked before the element from List2.
merge3(List1, List2, List3) -> List4
Types:
List1 = [X]
List2 = [Y]
List3 = [Z]
List4 = [(X | Y | Z)]
X = Y = Z = term()
Returns the sorted list formed by merging List1, List2 and List3. All of List1, List2 and List3
must be sorted prior to evaluating this function. When two elements compare equal, the element
from List1, if there is such an element, is picked before the other element, otherwise the element
from List2 is picked before the element from List3.
min(List) -> Min
Types:
List = [T, ...]
Min = T
T = term()
Returns the first element of List that compares less than or equal to all other elements of List.
nth(N, List) -> Elem
Types:
N = integer() >= 1
1..length(List)
List = [T, ...]
Elem = T
T = term()
Returns the Nth element of List. For example:
> lists:nth(3, [a, b, c, d, e]).
c
nthtail(N, List) -> Tail
Types:
N = integer() >= 0
0..length(List)
List = [T, ...]
Tail = [T]
T = term()
Returns the Nth tail of List, that is, the sublist of List starting at N+1 and continuing up to
the end of the list. For example:
> lists:nthtail(3, [a, b, c, d, e]).
[d,e]
> tl(tl(tl([a, b, c, d, e]))).
[d,e]
> lists:nthtail(0, [a, b, c, d, e]).
[a,b,c,d,e]
> lists:nthtail(5, [a, b, c, d, e]).
[]
partition(Pred, List) -> {Satisfying, NotSatisfying}
Types:
Pred = fun((Elem :: T) -> boolean())
List = Satisfying = NotSatisfying = [T]
T = term()
Partitions List into two lists, where the first list contains all elements for which Pred(Elem)
returns true, and the second list contains all elements for which Pred(Elem) returns false.
Examples:
> lists:partition(fun(A) -> A rem 2 == 1 end, [1,2,3,4,5,6,7]).
{[1,3,5,7],[2,4,6]}
> lists:partition(fun(A) -> is_atom(A) end, [a,b,1,c,d,2,3,4,e]).
{[a,b,c,d,e],[1,2,3,4]}
See also splitwith/2 for a different way to partition a list.
prefix(List1, List2) -> boolean()
Types:
List1 = List2 = [T]
T = term()
Returns true if List1 is a prefix of List2, otherwise false.
reverse(List1) -> List2
Types:
List1 = List2 = [T]
T = term()
Returns a list with the elements in List1 in reverse order.
reverse(List1, Tail) -> List2
Types:
List1 = [T]
Tail = term()
List2 = [T]
T = term()
Returns a list with the elements in List1 in reverse order, with the tail Tail appended. For
example:
> lists:reverse([1, 2, 3, 4], [a, b, c]).
[4,3,2,1,a,b,c]
seq(From, To) -> Seq
seq(From, To, Incr) -> Seq
Types:
From = To = Incr = integer()
Seq = [integer()]
Returns a sequence of integers which starts with From and contains the successive results of
adding Incr to the previous element, until To has been reached or passed (in the latter case, To
is not an element of the sequence). Incr defaults to 1.
Failure: If To<From-Incr and Incr is positive, or if To>From-Incr and Incr is negative, or if
Incr==0 and From/=To.
The following equalities hold for all sequences:
length(lists:seq(From, To)) == To-From+1
length(lists:seq(From, To, Incr)) == (To-From+Incr) div Incr
Examples:
> lists:seq(1, 10).
[1,2,3,4,5,6,7,8,9,10]
> lists:seq(1, 20, 3).
[1,4,7,10,13,16,19]
> lists:seq(1, 0, 1).
[]
> lists:seq(10, 6, 4).
[]
> lists:seq(1, 1, 0).
[1]
sort(List1) -> List2
Types:
List1 = List2 = [T]
T = term()
Returns a list containing the sorted elements of List1.
sort(Fun, List1) -> List2
Types:
Fun = fun((A :: T, B :: T) -> boolean())
List1 = List2 = [T]
T = term()
Returns a list containing the sorted elements of List1, according to the ordering function Fun.
Fun(A, B) should return true if A compares less than or equal to B in the ordering, false
otherwise.
split(N, List1) -> {List2, List3}
Types:
N = integer() >= 0
0..length(List1)
List1 = List2 = List3 = [T]
T = term()
Splits List1 into List2 and List3. List2 contains the first N elements and List3 the rest of the
elements (the Nth tail).
splitwith(Pred, List) -> {List1, List2}
Types:
Pred = fun((T) -> boolean())
List = List1 = List2 = [T]
T = term()
Partitions List into two lists according to Pred. splitwith/2 behaves as if it is defined as
follows:
splitwith(Pred, List) ->
{takewhile(Pred, List), dropwhile(Pred, List)}.
Examples:
> lists:splitwith(fun(A) -> A rem 2 == 1 end, [1,2,3,4,5,6,7]).
{[1],[2,3,4,5,6,7]}
> lists:splitwith(fun(A) -> is_atom(A) end, [a,b,1,c,d,2,3,4,e]).
{[a,b],[1,c,d,2,3,4,e]}
See also partition/2 for a different way to partition a list.
sublist(List1, Len) -> List2
Types:
List1 = List2 = [T]
Len = integer() >= 0
T = term()
Returns the sub-list of List1 starting at position 1 and with (max) Len elements. It is not an
error for Len to exceed the length of the list, in that case the whole list is returned.
sublist(List1, Start, Len) -> List2
Types:
List1 = List2 = [T]
Start = integer() >= 1
1..(length(List1)+1)
Len = integer() >= 0
T = term()
Returns the sub-list of List1 starting at Start and with (max) Len elements. It is not an error
for Start+Len to exceed the length of the list.
> lists:sublist([1,2,3,4], 2, 2).
[2,3]
> lists:sublist([1,2,3,4], 2, 5).
[2,3,4]
> lists:sublist([1,2,3,4], 5, 2).
[]
subtract(List1, List2) -> List3
Types:
List1 = List2 = List3 = [T]
T = term()
Returns a new list List3 which is a copy of List1, subjected to the following procedure: for each
element in List2, its first occurrence in List1 is deleted. For example:
> lists:subtract("123212", "212").
"312".
lists:subtract(A, B) is equivalent to A -- B.
Warning:
The complexity of lists:subtract(A, B) is proportional to length(A)*length(B), meaning that it
will be very slow if both A and B are long lists. (Using ordered lists and ordsets:subtract/2 is a
much better choice if both lists are long.)
suffix(List1, List2) -> boolean()
Types:
List1 = List2 = [T]
T = term()
Returns true if List1 is a suffix of List2, otherwise false.
sum(List) -> number()
Types:
List = [number()]
Returns the sum of the elements in List.
takewhile(Pred, List1) -> List2
Types:
Pred = fun((Elem :: T) -> boolean())
List1 = List2 = [T]
T = term()
Takes elements Elem from List1 while Pred(Elem) returns true, that is, the function returns the
longest prefix of the list for which all elements satisfy the predicate.
ukeymerge(N, TupleList1, TupleList2) -> TupleList3
Types:
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = [T1]
TupleList2 = [T2]
TupleList3 = [(T1 | T2)]
T1 = T2 = Tuple
Tuple = tuple()
Returns the sorted list formed by merging TupleList1 and TupleList2. The merge is performed on the
Nth element of each tuple. Both TupleList1 and TupleList2 must be key-sorted without duplicates
prior to evaluating this function. When two tuples compare equal, the tuple from TupleList1 is
picked and the one from TupleList2 deleted.
ukeysort(N, TupleList1) -> TupleList2
Types:
N = integer() >= 1
1..tuple_size(Tuple)
TupleList1 = TupleList2 = [Tuple]
Tuple = tuple()
Returns a list containing the sorted elements of the list TupleList1 where all but the first tuple
of the tuples comparing equal have been deleted. Sorting is performed on the Nth element of the
tuples.
umerge(ListOfLists) -> List1
Types:
ListOfLists = [List]
List = List1 = [T]
T = term()
Returns the sorted list formed by merging all the sub-lists of ListOfLists. All sub-lists must be
sorted and contain no duplicates prior to evaluating this function. When two elements compare
equal, the element from the sub-list with the lowest position in ListOfLists is picked and the
other one deleted.
umerge(List1, List2) -> List3
Types:
List1 = [X]
List2 = [Y]
List3 = [(X | Y)]
X = Y = term()
Returns the sorted list formed by merging List1 and List2. Both List1 and List2 must be sorted and
contain no duplicates prior to evaluating this function. When two elements compare equal, the
element from List1 is picked and the one from List2 deleted.
umerge(Fun, List1, List2) -> List3
Types:
Fun = fun((A, B) -> boolean())
List1 = [A]
List2 = [B]
List3 = [(A | B)]
A = B = term()
Returns the sorted list formed by merging List1 and List2. Both List1 and List2 must be sorted
according to the ordering function Fun and contain no duplicates prior to evaluating this
function. Fun(A, B) should return true if A compares less than or equal to B in the ordering,
false otherwise. When two elements compare equal, the element from List1 is picked and the one
from List2 deleted.
umerge3(List1, List2, List3) -> List4
Types:
List1 = [X]
List2 = [Y]
List3 = [Z]
List4 = [(X | Y | Z)]
X = Y = Z = term()
Returns the sorted list formed by merging List1, List2 and List3. All of List1, List2 and List3
must be sorted and contain no duplicates prior to evaluating this function. When two elements
compare equal, the element from List1 is picked if there is such an element, otherwise the element
from List2 is picked, and the other one deleted.
unzip(List1) -> {List2, List3}
Types:
List1 = [{A, B}]
List2 = [A]
List3 = [B]
A = B = term()
"Unzips" a list of two-tuples into two lists, where the first list contains the first element of
each tuple, and the second list contains the second element of each tuple.
unzip3(List1) -> {List2, List3, List4}
Types:
List1 = [{A, B, C}]
List2 = [A]
List3 = [B]
List4 = [C]
A = B = C = term()
"Unzips" a list of three-tuples into three lists, where the first list contains the first element
of each tuple, the second list contains the second element of each tuple, and the third list
contains the third element of each tuple.
usort(List1) -> List2
Types:
List1 = List2 = [T]
T = term()
Returns a list containing the sorted elements of List1 where all but the first element of the
elements comparing equal have been deleted.
usort(Fun, List1) -> List2
Types:
Fun = fun((T, T) -> boolean())
List1 = List2 = [T]
T = term()
Returns a list which contains the sorted elements of List1 where all but the first element of the
elements comparing equal according to the ordering function Fun have been deleted. Fun(A, B)
should return true if A compares less than or equal to B in the ordering, false otherwise.
zip(List1, List2) -> List3
Types:
List1 = [A]
List2 = [B]
List3 = [{A, B}]
A = B = term()
"Zips" two lists of equal length into one list of two-tuples, where the first element of each
tuple is taken from the first list and the second element is taken from corresponding element in
the second list.
zip3(List1, List2, List3) -> List4
Types:
List1 = [A]
List2 = [B]
List3 = [C]
List4 = [{A, B, C}]
A = B = C = term()
"Zips" three lists of equal length into one list of three-tuples, where the first element of each
tuple is taken from the first list, the second element is taken from corresponding element in the
second list, and the third element is taken from the corresponding element in the third list.
zipwith(Combine, List1, List2) -> List3
Types:
Combine = fun((X, Y) -> T)
List1 = [X]
List2 = [Y]
List3 = [T]
X = Y = T = term()
Combine the elements of two lists of equal length into one list. For each pair X, Y of list
elements from the two lists, the element in the result list will be Combine(X, Y).
zipwith(fun(X, Y) -> {X,Y} end, List1, List2) is equivalent to zip(List1, List2).
Example:
> lists:zipwith(fun(X, Y) -> X+Y end, [1,2,3], [4,5,6]).
[5,7,9]
zipwith3(Combine, List1, List2, List3) -> List4
Types:
Combine = fun((X, Y, Z) -> T)
List1 = [X]
List2 = [Y]
List3 = [Z]
List4 = [T]
X = Y = Z = T = term()
Combine the elements of three lists of equal length into one list. For each triple X, Y, Z of list
elements from the three lists, the element in the result list will be Combine(X, Y, Z).
zipwith3(fun(X, Y, Z) -> {X,Y,Z} end, List1, List2, List3) is equivalent to zip3(List1, List2,
List3).
Examples:
> lists:zipwith3(fun(X, Y, Z) -> X+Y+Z end, [1,2,3], [4,5,6], [7,8,9]).
[12,15,18]
> lists:zipwith3(fun(X, Y, Z) -> [X,Y,Z] end, [a,b,c], [x,y,z], [1,2,3]).
[[a,x,1],[b,y,2],[c,z,3]]