Question

How to get the first x leftmost digits of an integer number in JavaScript

Answer 1

function x_leftmost_digit(n, x) {
    x = Math.pow(10, x);
    while (n > x) {
        n = Math.floor(n / 10);
    }
    return n;
}

for (let i = 1; i <= 5; i++) {
    let n = Math.floor(Math.random() * 100000) + 1;
    let x = Math.floor(Math.random() * 5) + 1; 
    console.log(`${x} leftmost digit of ${n} is ${x_leftmost_digit(n, x)}`);
}



   
/*
run:
   
4 leftmost digit of 95779 is 9577
3 leftmost digit of 58846 is 588
5 leftmost digit of 12607 is 12607
4 leftmost digit of 6338 is 6338
2 leftmost digit of 69779 is 69
   
*/

 

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