String join with
You need to combine several items of a list into a string using a separator between each item representation.
In python, this is done by:
python> ','.join(['a', 'b', 'c']) 'a,b,c' python> ','.join(map(str, [1,2,3])) '1,2,3'
This solution interleave the input list with as many copy of the separator, then use the builtin concat function to create the final string:
string_join(Join, L) -> string_join(Join, L, fun(E) -> E end). string_join(_Join, L=, _Conv) -> L; string_join(Join, [H|Q], Conv) -> lists:flatten(lists:concat( [Conv(H)|lists:map(fun(E) -> [Join, Conv(E)] end, Q)] )).
Usage is as follow:
erl> test:string_join(",", ["1", "2", "3"]). "1,2,3" erl> test:string_join(",", [1, 2, 3], fun(X) -> io_lib:format("~B", [X]) end). "1,2,3"