Dick Moores wrote:
> At 05:54 AM 10/3/2006, Kent Johnson wrote:
>> Dick Moores wrote:
>>> Very interesting. I thought a line of that template looked
>>> familiar. I was seeing "_t0 = _timer()" regularly when I had the -s
>>> option set without any setup:
>>> C:\>python -m timeit -r 3 -s"for x in range(10000):" " x*x"
>>> Traceback (most recent call last):
>>> File "E:\Python25\lib\runpy.py", line 95, in run_module
>>> filename, loader, alter_sys)
>>> File "E:\Python25\lib\runpy.py", line 52, in _run_module_co
>>> mod_name, mod_fname, mod_loader)
>>> File "E:\Python25\lib\runpy.py", line 32, in _run_code
>>> exec code in run_globals
>>> File "E:\Python25\lib\timeit.py", line 285, in <module>
>>> sys.exit(main())
>>> File "E:\Python25\lib\timeit.py", line 249, in main
>>> t = Timer(stmt, setup, timer)
>>> File "E:\Python25\lib\timeit.py", line 116, in __init__
>>> code = compile(src, dummy_src_name, "exec")
>>> File "<timeit-src>", line 4
>>> _t0 = _timer()
>>> ^
>>> But I don't understand what the error has to do with _t0 . That's
>>> OK, don't bother to explain. I don't understand classes yet anyway.
>>> Should get into them soon, with Wes Chun's book.
>> If you substitute your code into the template by hand and look at
>> the actual exception (not shown above) you should see the problem.
>> It doesn't have anything to do with classes.
>
> I meant timeit.py has classes.
>
> OK, I called timeit.py with this template:
>
> template = """
> def inner(_it, _timer):
> %(setup)s
> _t0 = _timer()
> for _i in _it:
> %("x=0" "while x<100": " x*x")s
> _t1 = _timer()
> return _t1 - _t0
> """
OK, let's go back to your first example and I will explain in more detail.
timeit.py contains this template:
template = """
def inner(_it, _timer):
%(setup)s
_t0 = _timer()
for _i in _it:
%(stmt)s
_t1 = _timer()
return _t1 - _t0
"""
Whatever you specify for setup code is substituted for %(setup)s; the
timed statement is substituted for %(stmt)s. This is done using standard
string formatting operations. The result of the substitutions is a
function definition which is compiled and run.
So if you run
python -m timeit -s"for x in range(10000):" " x*x"
the generated function looks like this:
def inner(_it, _timer):
for x in range(10000):
_t0 = _timer()
for _i in _it:
x*x
_t1 = _timer()
return _t1 - _t0
The for statement should begin an indented block; the next statement is
*not* indented, so you get an IndentationError.
Does that help?
Kent
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