How to generate a random 4 digit number not starting with 0 and having unique digits?

Question

This works almost fine but the number starts with 0 sometimes:

import random
numbers = random.sample(range(10), 4)
print(\'\'.join(map(str, numbers)))
         


        

Answer 1

rejection sampling method. Create a 4 digit random combination from 10 digits and resample if it doesn't match the criteria.

r4=0    
while r4 < 1000:
    r4=int(''.join(map(str,random.sample(range(10),4))))

noticed that this is essentially the same as @Austin Haskings's answer