python -m timeit: SyntaxError: from future imports must occur at the beginning of the file

Question

I'd like to compare the execution time in different ways of forcing division to be floating point.

While testing the following code with timeit in terminal,

from __future__ import division
a = 2/3

I encounter the error,

$ python -m timeit '2*1.0/3'    # this works
10000000 loops, best of 3: 0.0578 usec per loop

$ python -m timeit -s 'from __future__ import division' '2/3'
Traceback (most recent call last):
  File "/usr/lib/python2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/usr/lib/python2.7/timeit.py", line 330, in <module>
    sys.exit(main())
  File "/usr/lib/python2.7/timeit.py", line 294, in main
    t = Timer(stmt, setup, timer)
  File "/usr/lib/python2.7/timeit.py", line 136, in __init__
    code = compile(src, dummy_src_name, "exec")
  File "<timeit-src>", line 3
SyntaxError: from __future__ imports must occur at the beginning of the file

How do I measure the execution time for such a snippet code?

score 1 · Accepted Answer · answered May 14 '16 at 02:51

1

By enabling the behavior globally:

$ python -Q new -m timeit '2/3'
10000000 loops, best of 3: 0.0242 usec per loop

answered May 14 '16 at 02:51

Ignacio Vazquez-Abrams

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In such a case, `2/3` equals `0.66` or `0`? – SparkAndShine May 14 '16 at 02:55
@sparkandshine: Did you look at the man page to see what `-Q` does? – Ignacio Vazquez-Abrams May 14 '16 at 02:56

python -m timeit: SyntaxError: from __future__ imports must occur at the beginning of the file

1 Answers1

python -m timeit: SyntaxError: from future imports must occur at the beginning of the file