%timeit equivalent in code

Assuming you can use/import IPython, and you simply want to create a headless script that uses the %timeit magic, you could do something like the following.

Assume the following is in the file testme.py:

from IPython import get_ipython

def myfun(x):
    return x**x

val = 12.3
out = get_ipython().run_line_magic("timeit","-o myfun({})".format(val))

#do something with out, which will be a TimeitResult object

Then you can run the script non-interactively with:

ipython testme.py

The magic %timeit command offers a -o option:

-o: return a TimeitResult that can be stored in a variable to inspect the result in more details.

It will still print the result but also return the result so that it can be captured in a variable. The syntax for magic commands is a bit limited but you could collect different results in a list by assigning it to a variable and appending that variable to a list:

res = []
for i in range(3):
    a = %timeit -o 10*10
    res.append(a)
# 10000000 loops, best of 3: 61 ns per loop
# 10000000 loops, best of 3: 61.1 ns per loop
# 10000000 loops, best of 3: 60.8 ns per loop

and then access res:

print(res)
# [<TimeitResult : 10000000 loops, best of 3: 61.2 ns per loop>,
#  <TimeitResult : 10000000 loops, best of 3: 61.3 ns per loop>,
#  <TimeitResult : 10000000 loops, best of 3: 61.5 ns per loop>]

Each of these results has several attributes, which might be of interest:

print(res[0].all_runs)
# [0.6166532894762563, 0.6102780388983005, 0.6370787790842183]
print(res[0].best)
# 6.102780388983005e-08
print(res[0].compile_time)
# 0.00020554513866197934
print(res[0].loops)
# 10000000
print(res[0].repeat)
# 3
print(res[0].worst)
# 1.1170931449020795e-06

To plot for example the best times you need to create a new list containing the best values:

res_best_times = [result.best * 1e9 for result in res] 
# "* 1e9" to get the result in nanoseconds
print(res_best_times)
# [61.2, 61.3, 61.5]