How to make "zip" work faster?

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I have these two finite sets $A$ and $B$ where the size of $A$ is typically much larger than the size of $B$. (typically $|A| is 200-500$ and $|B| is 10-50$) I am trying to enumerate all possible maps from $B$ to $A$ using the following idea - but this turns out to be very slow.

• Is there a way to speed this up?

  • Without the over all "for i" loop can I access any one of the "k"s? (for every i each $l$ is a list of tuples)

  How can I just pick out any one such "k" list without wanting to wait for the whole code to run.

  S = []
  from itertools import product
  
  for i in product(A,repeat = len (B)):
  
      k = zip(B,i)
      S.append(k)
  
  
  show(S)