CODEWITHSUNDEEP
javascriptrandom
mridul
mridul

Reputation: 2096

generate random number using specific digits in javascript

In my program I want to generate 5 digit random number such the that contain only digits ( 1 to 7).

var randnum = Math.floor(Math.random() * (11111 - 77777 + 1)) + 11111;

Using above code I got number between 11111 and 77777. But how to generate the number that does not contain 0,8,9 ? Is there any default method to generate this kind of numbers?

Upvotes: 2

Views: 1442

Answers (2)

Tibos
Tibos

Reputation: 27853

You can generate each digit at a time, concatenate them then parseInt to get your result:

var str = '';
for (var i=0; i<5; i++) {
  str += Math.floor(Math.random()*7) + 1;
}
var randnum = parseInt(str);

Demo

Explanation

Math.random() returns [0,1)

Math.random() * 7 returns [0,7)

Math.floor(...) returns 0,1,2,3,4,5,6

...+1 returns 1,2,3,4,5,6,7

Upvotes: 2

georg
georg

Reputation: 215059

For example,

digits = [1,2,3,4,5,6,7]
len = 5
num = 0
while(len--)
    num = num * 10 + digits[Math.floor(Math.random() * digits.length)]
console.log(num)

This way you can easily select which digits to use.

Upvotes: 1

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