CODEWITHSUNDEEP
pythonrandomrandom-seed
bbiot426
bbiot426

Reputation: 37

Random values are going weird in conditional statement with seed

from random import seed,random
for i in range(21):
     if i%3==0:
         seed(10)
     if i%2==0:
         random()
     else:
         random()

with above code, result is

0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704

which,

a=0.5714025946899135
b=0.4288890546751146
c=0.5780913011344704

is continuously repeating.

But according to seed(10), i should get only a=0.5714025946899135 with a seed applyed,

and the others should be random.

but why other value (0.4288890546751146 and 0.5780913011344704) is constant too?

Upvotes: 0

Views: 65

Answers (1)

Thomas Kimber
Thomas Kimber

Reputation: 11067

seed(10) sets the seed and resets the random number generator for that seed. So every 3rd iteration, you're just starting the random numbers (for seed = 10) back to the beginning. If you want different numbers, you need to set the seed to something else (ideally a random number, or leave blank which achieves this last option)

Put it another way, the random numbers that come out of random are deterministic. Given a seed, the output of the random function will be random when looked at as a series, but one that is pre-determined. Every time you pull numbers from a given seed, you'll get the exact same, random numbers, in the same sequence.

Upvotes: 6

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