http://www.python.org/doc/essays/list2str.html http://www.python.org/doc/essays/f.py

f.py

def f1(list):
    string = ""
    for item in list:
        string = string + chr(item)
    return string

def f2(list):
    return reduce(lambda string, item: string + chr(item), list, "")

def f3(list):
    string = ""
    for character in map(chr, list):
        string = string + character
    return string

def f4(list):
    string = ""
    lchr = chr
    for item in list:
        string = string + lchr(item)
    return string

def f5(list):
    string = ""
    for i in range(0, 256, 16): # 0, 16, 32, 48, 64, ...
        s = ""
        for character in map(chr, list[i:i+16]):
            s = s + character
        string = string + s
    return string

import string
def f6(list):
    return string.joinfields(map(chr, list), "")

import array
def f7(list):
    return array.array('B', list).tostring()

from struct import pack
def f8(list):
    return pack('%dB' % len(list), *list)

def cmpthese(n=0, functions=None):
    results = {}
    for func_name in functions:
        args = ['%s(range(256))' % func_name, 'from __main__ import %s' % func_name]
        t = Timer(*args)
        results[func_name] = 1 / (t.timeit(number=n) / n) # passes/sec

    functions_sorted = sorted(functions, key=results.__getitem__)
    for f in functions_sorted:
        diff = []
        for func in functions_sorted:
            if func == f:
                diff.append("    --")
            else:
                diff.append("%5.0f%%" % (results[f]/results[func]*100 - 100))
        diffs = " ".join(diff)

        print "%s\t%6d/s %s" % (f, results[f], diffs)


if __name__=='__main__':
    from timeit import Timer
    cmpthese(1000, 'f1 f2 f3 f4 f5 f6 f7 f8'.split(" "))

f2    9921/s     --   -27%   -44%   -46%   -47%   -63%   -81%   -90%
f5   13654/s    38%     --   -23%   -25%   -27%   -49%   -74%   -86%
f1   17682/s    78%    29%     --    -3%    -5%   -34%   -67%   -82%
f4   18261/s    84%    34%     3%     --    -2%   -32%   -66%   -82%
f3   18643/s    88%    37%     5%     2%     --   -30%   -65%   -81%
f6   26791/s   170%    96%    52%    47%    44%     --   -50%   -73%
f7   53535/s   440%   292%   203%   193%   187%   100%     --   -46%
f8   98992/s   898%   625%   460%   442%   431%   269%    85%     --