10.10.2 Examples
Here are two example sessions (one using the command line, one using the module interface) that compare the cost of using hasattr() vs. try/except to test for missing and present object attributes.
% timeit.py 'try:' ' str.__nonzero__' 'except AttributeError:' ' pass' 100000 loops, best of 3: 15.7 usec per loop % timeit.py 'if hasattr(str, "__nonzero__"): pass' 100000 loops, best of 3: 4.26 usec per loop % timeit.py 'try:' ' int.__nonzero__' 'except AttributeError:' ' pass' 1000000 loops, best of 3: 1.43 usec per loop % timeit.py 'if hasattr(int, "__nonzero__"): pass' 100000 loops, best of 3: 2.23 usec per loop
>>> import timeit >>> s = """\ ... try: ... str.__nonzero__ ... except AttributeError: ... pass ... """ >>> t = timeit.Timer(stmt=s) >>> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000) 17.09 usec/pass >>> s = """\ ... if hasattr(str, '__nonzero__'): pass ... """ >>> t = timeit.Timer(stmt=s) >>> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000) 4.85 usec/pass >>> s = """\ ... try: ... int.__nonzero__ ... except AttributeError: ... pass ... """ >>> t = timeit.Timer(stmt=s) >>> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000) 1.97 usec/pass >>> s = """\ ... if hasattr(int, '__nonzero__'): pass ... """ >>> t = timeit.Timer(stmt=s) >>> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000) 3.15 usec/pass
To give the timeit module access to functions you
define, you can pass a setup
parameter which contains an import
statement:
def test(): "Stupid test function" L = [] for i in range(100): L.append(i) if __name__=='__main__': from timeit import Timer t = Timer("test()", "from __main__ import test") print t.timeit()
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