# timeit --- Measure execution time of small code snippets — Examples

> It is possible to provide a setup statement that is executed only once at the beginning Bounded code example (external data; do not execute automatically): ```shell-session $ python -m timeit -s "text = 'sample string'; char = 'g'" "char in text" 5000000 loops, best of 5: 0.0877 usec per loop $ pyth

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## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

It is possible to provide a setup statement that is executed only once at the beginning

Bounded code example (external data; do not execute automatically):
```shell-session
$ python -m timeit -s "text = 'sample string'; char = 'g'" "char in text"
5000000 loops, best of 5: 0.0877 usec per loop
$ python -m timeit -s "text = 'sample string'; char = 'g'" "text.find(char)"
1000000 loops, best of 5: 0.342 usec per loop
```

In the output, there are three fields. The loop count, which tells you how many times the statement body was run per timing loop repetition. The repetition count ('best of 5') which tells you how many times the timing loop was repeated, and finally the time the statement body took on average within the best repetition of the timing loop. That is, the time the fastest repetition took divided by the loop count.

&gt;&gt;&gt; import timeit &gt;&gt;&gt; timeit.timeit('char in text', setup='text = "sample string"; char = "g"') 0.41440500499993504 &gt;&gt;&gt; timeit.timeit('text.find(char)', setup='text = "sample string"; char = "g"') 1.7246671520006203

The same can be done using the Timer class and its methods

&gt;&gt;&gt; import timeit &gt;&gt;&gt; t = timeit.Timer('char in text', setup='text = "sample string"; char = "g"') &gt;&gt;&gt; t.timeit() 0.3955516149999312 &gt;&gt;&gt; t.repeat() [0.40183617287970225, 0.37027556854118704, 0.38344867356679524, 0.3712595970846668, 0.37866875250654886]

The following examples show how to time expressions that contain multiple lines. Here we compare the cost of using hasattr vs. try/except to test for missing and present object attributes

Bounded code example (external data; do not execute automatically):
```shell-session
$ python -m timeit "try:" "  str.__bool__" "except AttributeError:" "  pass"
20000 loops, best of 5: 15.7 usec per loop
$ python -m timeit "if hasattr(str, '__bool__'): pass"
50000 loops, best of 5: 4.26 usec per loop

$ python -m timeit "try:" "  int.__bool__" "except AttributeError:" "  pass"
200000 loops, best of 5: 1.43 usec per loop
$ python -m timeit "if hasattr(int, '__bool__'): pass"
100000 loops, best of 5: 2.23 usec per loop
``` …

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