Random generator from 1-7 from a given random generator 1-5

INPUT: import random def rand5(): return random.randint(1, 5) def rand7(): """ Generating 25 random numbers uniformly between 1-25 and picking up modulo 7 from first 21 of them 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 2 3 4 5 6 7 - - - - """ while True: # x is uniformly generated between 1-25 x = 5 * (rand5() - 1) + rand5() if (x <= 21): # Ignore >21 numbers break # Result is now uniformly random between 1-7 return x % 7 + 1 def distribution(foo): d = {} for _ in xrange(10000): x = foo() if x not in d: d[x] = 0 d[x] += 1 return d print distribution(rand7) print distribution(rand5) OUTPUT: {1: 1446, 2: 1422, 3: 1417, 4: 1442, 5: 1459, 6: 1403, 7: 1411} {1: 1995, 2: 2016, 3: 1999, 4: 1992, 5: 1998}

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