Convert a list of characters into a string


If I have a list of chars:

a = ['a','b','c','d']

How do I convert it into a single string?

a = 'abcd'

Answer

besides str.join which is the most natural way, a possibility is to use io.StringIO and abusing writelines to write all elements in one go:

import io

a = ['a','b','c','d']

out = io.StringIO()
out.writelines(a)
print(out.getvalue())

prints:

abcd

When using this approach with a generator function or an iterable which isn't a tuple or a list, it saves the temporary list creation that join does to allocate the right size in one go (and a list of 1-character strings is very expensive memory-wise).

If you're low in memory and you have a lazily-evaluated object as input, this approach is the best solution.