how to pass parameters of a function when using timeit.Timer()

Question

This is the outline of a simple program

# some pre-defined constants
A = 1
B = 2

# function that does something critical
def foo(num1, num2):
    # do something

# main program.... do something to A and B
for i in range(20):
    # do something to A and B
    # and update A and B during each iteration

import timeit
t = timeit.Timer(stmt="foo(num1,num2)")  
print t.timeit(5)

I just keep getting "global name foo is not defined"..... Can anyone help me on this? Thanks!

Answer 1

The functions can use arguments in timeit if these are created using closures, we can add this behaviours by wrapping them in another function.

def foo(num1, num2):
    def _foo():
        # do something to num1 and num2
        pass
    return _foo

A = 1
B = 2

import timeit
t = timeit.Timer(foo(A,B))  
print(t.timeit(5))

or shorter, we can use functools.partial instead of explicit closures declaration

def foo(num1, num2):
    # do something to num1 and num2
    pass

A = 1
B = 2

import timeit, functools
t = timeit.Timer(functools.partial(foo, A, B)) 
print(t.timeit(5))

EDIT using lambda, thanks @jupiterbjy

we can use lambda function without parameters instead of functools library

def foo(num1, num2):
    # do something to num1 and num2
    pass

A = 1
B = 2

import timeit
t = timeit.Timer(lambda: foo(A, B)) 
print (t.timeit(5))