Shortest code for random number between 1 and N in JavaScript
Here I want to show you a tip for creating a random number between 1 and N in easiest and shortest way.
Code
Here is the code:
~~(Math.random() * N) + 1All you need to do is to replace N with your upper number.
How?
In JavaScript we have Math.random() which creates a random number between 0 and 1, e.g. 0.3577353348955512. We use this function to have a random number, then we multiply that to our upper number (e.g. 6):
0.3577353348955512 * 6 = 2.1464120093733072And then we get the floor number with double ~ operator (see this tip: https://coderwall.com/p/9b6ksa).
Written by Afshin Mehrabani
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6 Responses
And for the same with -ve random numbers: ~(Math.random() * N)
+1 for the ~~ operator, I didn't actually know that you can floor numbers like that, thanks for sharing
Please, forgive my dumb question. What is the point of the +1?
If Math.random()returns a random number between 0 and 1, in case of 1:
1 * 6 + 1This returns 7.
Math.random() return a random number between 0 (inclusive) and 1 (exclusive).
Thanks, @as32!
Math.floor is faster in new version of v8 ;)
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