Testing random

[Peter Otten]

Steven D'Aprano wrote:


>> I wrote a very simple function to test random:
>>     def test_random(length, multiplier = 10000):
>>         number_list = length * [0]
>>         for i in range(length * multiplier):
>>             number_list[random.randint(0, length - 1)] += 1
>>         minimum = min(number_list)
>>         maximum = max(number_list)
>>         return (minimum, maximum, minimum / maximum)
> 
> Putting aside the timing aspects, your frequency calculations are not done
> in a very Pythonic manner. 

I would agree if the frequency table were sparse, i. e. many indices with

number_list[index] == 0

but that's not the case with on average 10000 hits per index.

> A better way might be:

I'm too lazy to measure, but this will likely be a tad slower. Did you mean 
to convey this by "Putting aside the timing aspects"?

> from collections import Counter
> from random import randint
> 
> def test_random(length, multiplier = 10000):
>     freq = Counter(
>         randint(0, length - 1) for i in range(length * multiplier)
>         )
>     minimum = min(freq[i] for i in range(length))

How about

      if len(freq) < length:
          minimum = 0
      else:
          minimum = min(freq.values())

Not as an optimisation (replacing randint() with randrange() is probably 
more effective in that department), but because it's closer to being self-
explanatory.

>     maximum = max(freq.values())
>     return (minimum, maximum, minimum / maximum)