smarnach

import timeit

a = range(10000)
da = set(a)

def list_first():
    return 0 in a

def set_first():
    return 0 in da

smarnach

In [1]: a = 256

In [2]: b = 256

In [3]: a is b
Out[3]: True

In [4]: a = 257

In [5]: b = 257

smarnach

def compose(*funcs):
    def comp(x):
        for f in reversed(funcs):
            x = f(x)
        return x
    return comp

smarnach

In [1]: %timeit sum([(0, 0)] * 1000, ())
100 loops, best of 3: 5.01 ms per loop

In [2]: %timeit sum([(0, 0)] * 10000, ())
1 loops, best of 3: 490 ms per loop

In [3]: %timeit sum([(0, 0)] * 100000, ())
1 loops, best of 3: 61.9 s per loop

smarnach

>>> timeit.repeat("for i in xrange(1000): a.append(i)",
...               "from collections import deque; a = deque()", number=10000)
[1.139456033706665, 1.1287789344787598, 1.129647970199585]
>>> timeit.repeat("for i in xrange(1000): a.append(i)", "a = []", number=10000)
[1.1056618690490723, 1.0919761657714844, 1.0903148651123047]

smarnach

>>> timeit.repeat("a = deque()\nfor i in xrange(10000): a.append(i)\nfor x in a: x",
...               "from collections import deque", number=1000)
[1.4415068626403809, 1.4344120025634766, 1.4339849948883057]
>>> timeit.repeat("a = []\nfor i in xrange(10000): a.append(i)\nfor x in a: x", number=1000)
[1.3635458946228027, 1.3510761260986328, 1.3518819808959961]

smarnach

Python 2.7.2+ (default, Jun 29 2011, 00:07:42) 
[GCC 4.6.1 20110616 (prerelease)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> class A(object):
...     pass 
... 
>>> A.__doc__ = "doc"
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: attribute '__doc__' of 'type' objects is not writable

smarnach

#include <unistd.h>
#include <stdio.h>

int main(int argc, const char **argv)
{
    char c[10240] = {0};
    int fd;

    sscanf(argv[1] + 8, "%i", &fd);    // skip "/dev/fd/"
    read(fd, c, 10239);

smarnach

Tmimings on a Linux box, 32-bit kernel, 32-bit userland

Python version:                                        2.7                    3.1
-s"a=10**20;n=3" "(a>>n)&1"                   0.224 usec per loop     0.161 usec per loop
-s"a=10**20;n=3" "not not(a & (1 << n))"      0.155 usec per loop     0.183 usec per loop
-s"a=10**200;n=3" "(a>>n)&1"                  0.39 usec per loop      0.303 usec per loop
-s"a=10**200;n=3" "not not(a & (1 << n))"     0.158 usec per loop     0.177 usec per loop
-s"a=10**10;n=3" "(a>>n)&1"                   0.223 usec per loop     0.153 usec per loop
-s"a=10**10;n=3" "not not(a & (1 << n))"      0.158 usec per loop     0.18 usec per loop
-s"a=10**9;n=3" "(a>>n)&1"                    0.0734 usec per loop    0.152 usec per loop

smarnach

In [3]: consume = collections.deque(maxlen=0).extend

In [4]: def f(a):
   ...:     consume(x for x in a)
   ...:     

In [5]: def g(a):
   ...:     consume(a)
   ...: