What is the preferred way to concatenate strings in python

Question

Since Python's string can't be changed, I was wondering how to concatenate a string more efficiently?

I can write like it:

s += stringfromelsewhere

or like this:

s = []
s.append(somestring)

later

s = ''.join(s)

But it's in Python 2.x., so the question would be did something change in Python 3?

Answer 1

If the strings you are concatenating are literals, use String literal concatenation

re.compile(
        "[A-Za-z_]"       # letter or underscore
        "[A-Za-z0-9_]*"   # letter, digit or underscore
    )

This is useful if you want to comment on part of a string (as above) or if you want to use raw stringsor triple quotes for part of a literal but not all.

Since this happens at the syntax layer it uses zero concatenation operators.