Python string concatenation performance

A small test revealed that "".join(listOfStrings) is not faster than plain +=. The .join() is slower. Using .append() and .join() is slower.

Time with .join():

real    0m2.908s

Time with +=:

real    0m1.742s

The test:

#!/usr/bin/env python

def combine(inc, count):
    text = ""
    for i in xrange(count):
        text += inc
    return len(text)

def combineByJoin(inc, count):
    text = []
    for i in xrange(count):
        text.append(inc)
    text = "".join(text)
    return len(text)

def main():
    inc = "a" * 10
    print combine(inc, 10000000)
    #print combineByJoin(inc, 10000000)

main()

Tested on Python 2.5.2.