How to get a random value from 1~N but excluding several specific values in PHP?

Question

rand(1,N) but excluding array(a,b,c,..),

is there already a built-in function that I don\'t know or do I have to implement it myself(how?)

Answer 1

I don't think there's such a function built-in ; you'll probably have to code it yourself.

To code this, you have two solutions :

• Use a loop, to call rand() or mt_rand() until it returns a correct value
  • which means calling rand() several times, in the worst case
  • but this should work OK if N is big, and you don't have many forbidden values.
• Build an array that contains only legal values
  • And use array_rand to pick one value from it
  • which will work fine if N is small