Comparing mem usage of str catenation and list joining

catenation.py

import os, random, string

nobjs = int(1e7)
objsz = 1

print 'str catenation'
print

s = ''
for i in range(nobjs):
    randchars = ''.join(random.choice(string.ascii_uppercase + string.digits) for x in range(objsz))
    s += randchars


os.system('ps -p %s -o "%%mem"' % os.getpid())

chunks.py

import os, random, string

nobjs = int(1e7)
objsz = 1

print 'chunks'
print
chunks = []
for i in range(nobjs):
    randchars = ''.join(random.choice(string.ascii_letters) for x in range(objsz))
    chunks.append(randchars)

os.system('ps -p %s -o "%%mem"' % os.getpid())

$ time python catenation.py
str catenation

%MEM
4.0

real 0m43.178s
user 0m42.979s
sys 0m0.191s
$ time chunks.py
chunks

%MEM
4.8

real 0m39.946s
user 0m39.707s
sys 0m0.231s