Can Python generate a random number that excludes a set of numbers, without using recursion?

Generate one random number and map it onto your desired ranges of numbers.

If you wanted to generate an integer between 1-4 or 7-10, excluding 5 and 6, you might:

1. Generate a random integer in the range 1-8
2. If the random number is greater than 4, add 2 to the result.

The mapping becomes:

Random number:    1  2  3  4  5  6  7  8
Result:           1  2  3  4  7  8  9 10

Doing it this way, you never need to “re-roll”. The above example is for integers, but it can also be applied to floats.