Join. letters does not work, when list in list?

Hello,

my code works fine:

strings = IN[0]

OUT = ",".join(strings)

when i try to make the same in a list of lists it does not work:

strings = IN[0]

OUT = []

for x in strings:
    for i in x:
        OUT.append(",".join(i))

#desired result:
1,2,1
4,5,3
0,2,3

You are appending the result into a flat list.

Append to a new list defined in the outer loop, then after finishing the inner loop append the outer loop to the result.

Generally speaking you should try to keep OUT as a static variable, and not define it twice.

@Draxl_Andreas Or you can use list comprehension by always converting the input to a nested list

toNestList = lambda x: x if any(isinstance(i, list) for i in x) else [x]
OUT = [",".join(x) for x in toNestList(IN[0])]