Why does %timeit loop different number of times?

Question

On Jupter Notebook, i was trying to compare time taken between the two methods for finding the index with max value.

In the Image, the first function took, 1000

Answer 1

It has a built-in option -n: " Options: -n: execute the given statement times in a loop. If this value is not given, a fitting value is chosen."docs

So it choses the number of loops itself if not specified.

Answer 2

use -r to limit the number of run's:

import time
%timeit -r1 time.sleep(2)
# 2 s ± 0 ns per loop (mean ± std. dev. of 1 run, 1 loop each)

%timeit -r4 time.sleep(2)
# 2 s ± 800 µs per loop (mean ± std. dev. of 4 runs, 1 loop each)

%timeit time.sleep(2)
# 2 s ± 46.5 µs per loop (mean ± std. dev. of 7 runs, 1 loop each)

Answer 3

%timeit library will limit the number of runs depending on how long the script takes to execute.

The number of runs may be set with -n. Example:

%timeit -n 5000
df = pd.DataFrame({'High':[1,4,8,4,0]})

5000 loops, best of 3: 592 µs per loop