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#!/usr/bin/env python
#
# A script for timing snippets of Python code.
import time
Now = time.time
#Now = time.clock # better on Windows, some UNIX/Linux systems
# How many times each snippet of code will be run by the functions
# to gather the time (the "inner loop").
Iterations = 10000
# How many times we'll run each function to collect its aggregate time
# and try to average out timing differences induced by system performance
# (the "outer loop").
Runs = 10
# The functions containing the code snippets to test and compare.
# This script will test any function whose name begins with the string
# "Func" and assumes that they all get passed the same arguments.
# Each function should put its snippet within a block:
#
# for i in IterationList:
#
# So that (as much as possible) we're testing just the code itself,
# not Python function call overhead.
def Func1(var, gvars, lvars):
for i in IterationList:
try:
x = lvars[var]
except KeyError:
try:
x = gvars[var]
except KeyError:
x = ''
def Func2(var, gvars, lvars):
for i in IterationList:
if lvars.has_key(var):
x = lvars[var]
else:
try:
x = gvars[var]
except KeyError:
x = ''
def Func3(var, gvars, lvars):
for i in IterationList:
if lvars.has_key(var):
x = lvars[var]
elif gvars.has_key(var):
x = gvars[var]
else:
x = ''
def Func4(var, gvars, lvars):
for i in IterationList:
try:
x = eval(var, gvars, lvars)
except NameError:
x = ''
# Data to pass to the functions on each run. Each entry is a
# three-element tuple:
#
# (
# "Label to print describing this data run",
# ('positional', 'arguments'),
# {'keyword' : 'arguments'},
# ),
Data = [
(
"Neither in gvars or lvars",
('x', {}, {}),
{},
),
(
"Missing from lvars, found in gvars",
('x', {'x':1}, {}),
{},
),
(
"Found in lvars",
('x', {'x':1}, {'x':2}),
{},
),
]
IterationList = [None]
def timer(func, *args, **kw):
global IterationList
IterationList = [None] * Iterations
results = []
for i in range(Runs):
start = Now()
func(*args, **kw)
finish = Now()
results.append((finish - start) / Iterations)
return results
def display(label, results):
print ' ' + label + ':'
print ' ',
for r in results:
print "%.3f" % (r * 1e6),
print
def display(label, results):
total = reduce(lambda x, y: x+y, results, 0.0)
print " %8.3f" % ((total * 1e6) / len(results)), ':', label
func_names = filter(lambda x: x.startswith('Func'), locals().keys())
func_names.sort()
for f in func_names:
func = locals()[f]
print f + ':'
for label, args, kw in Data:
r = apply(timer, (func,)+args, kw)
display(label, r)
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