CODEWITHSUNDEEP
pythonrandomsequence
bsils
bsils

Reputation: 25

Generating random numbers in range until a max for that number has been met in python

I'm trying to do something basic - use range 0-4 and generate a 36 number sequence such that each value is generated 9 times.

The var trial_init is just an array of 36 zeros.

I have generated:

trial_seq = []

for i in range(len(trial_init)-1):    
    while True:
        trial_val = random.choice(range(4))
        if (trial_seq.count(0) <=9 and trial_seq.count(1) <=9 and trial_seq.count(2) <=9 and trial_seq.count(3) <=9):
            break
    trial_seq.append(trial_val)

I guess I'm not sure exactly why it doesn't work.

It should generate a number 0, 1, 2 or 3 and to the extent that number has not been included in the trial_seq array more than 9 times, it should add it to the trial_seq array, otherwise it should generate another number, until 36 numbers have been generated.

Upvotes: 0

Views: 126

Answers (1)

Marcus M&#252;ller
Marcus M&#252;ller

Reputation: 36472

I assume this is python.

You could actually go the other way around: generate an index set, and randomly assign indices from that to each of the four possible values:

trial_seq = [0]*36
indices = range(36)
random.shuffle(indices)
for i in range(36):
    trial_seq[indices[i]] = i % 4;

EDIT: Oh man, at times I'm stupid:

trial_seq = [ i % 4 for i in xrange(36) ]
random.shuffle(trial_seq)

does the same.

Upvotes: 1

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