title: Biased Random Number Generator
body: <p>I am looking for a random number generator that can be biased. For instance, say I want a random number between 1-5, with the probability being:</p>
  
  <p>1: Comes up 20% of the time<br>
  2: Comes up 10% of the time<br>
  3: Comes up 40% of the time<br>
  4: Comes up 25% of the time<br>
  5: Comes up 5% of the time  </p>
  
  <p>Is there anything in the standard library, or other libraries out there that would do this? Alternatively, is there an efficient way to do this myself?</p>