In JavaScript, I may have a random number generated, that may be 3,123, or 3,001, or 2790, etc.. Which JavaScript method will help me out in returning a target whole integer because these values...

3,123, or 3,001, or 2790 are closer to 3000, rather than 4000 or 2000, or 1000.

Thanks for any advice.

In JavaScript, I may have a random number generated, that may be 3,123, or 3,001, or 2790, etc.. Which JavaScript method will help me out in returning a target whole integer because these values...

3,123, or 3,001, or 2790 are closer to 3000, rather than 4000 or 2000, or 1000.

Thanks for any advice.

• javascript

Share Improve this question Follow edited Sep 25, 2012 at 20:47 klewis asked Sep 25, 2012 at 20:00 klewisklewis 8,4381616 gold badges6969 silver badges112112 bronze badges 2

• 1 Your question is not clear, do you want to get the closest thousand of a number, the closest to a given target, the different distances towards a target, or something else? – Mahn Commented Sep 25, 2012 at 20:17
• I fixed up my question for you Mahn – klewis Commented Sep 25, 2012 at 20:47

Add a ment  | 

2 Answers 2

Sorted by: Reset to default 5

You could sort them:

var numbers = [3123, 3001, 2790, 4000, 2000, 1000];
var target = 3000;
var closest = numbers.sort(function(a, b) {
  var a = Math.abs(a - target);
  var b = Math.abs(b - target);

  return a < b ? -1 : (a > b ? 1 : 0);
});

closest contains the numbers sorted by their distance from 3000.

Or you could use a long one-liner:

var sorted = numbers.map(function(value, index) {
  return [Math.abs(value - 3000), index];
}).sort().map(function(value, index) {
  return numbers[value[1]];
});

Try:

var rand_num = Math.floor(Math.random() * 10000);
Math.round((rand_num) / 1000) * 1000;

If rand_num is 3123, 3001 or 2790, it will be reduced to either 3.123, 3.001 and 2.729 respectively, rounded to 3.0 and multiplied to bee 3000.