Sort array in ascending order

Question

Array: var ranges = ["3-5", "1-4", "0-9", "10-10"];

I tried the following function:

ranges.sort();

// Output: 0-9,1-4,10-10,3-5

// Desired output: 0-9,1-4,3-5,10-10

Any idea how I can get to desired output?

Answer 1

If you want to sort by the first number, the approach is:

var desire = ranges.sort(function(a,b){return parseInt(a)-parseInt(b)});

Explanation: parseInt(a) just removes everything after the non-number, i.e. - and returns the number.

If you also want to make it sort by the first number properly if you have ranges starting with the same numbers (i.e. 3-5 and 3-7):

var desire = ranges.sort(function(a,b){
   return (c=parseInt(a)-parseInt(b))?c:a.split('-')[1]-b.split('-')[1]
});

Explanation: works as the first one until the first numbers are equal; then it checks for the second numbers (thanks Michael Geary for idea!)

If you want to sort by the result of equation, go for

var desire = ranges.sort(function(a,b){return eval(a)-eval(b)});

Explanation: eval(a) just evaluates the expression and passes the result.

Also, as mentioned by h2ooooooo, you can specify the radix to avoid unpredictable behavior (i.e. parseInt(a, 10)).

Answer 2

Here's one more:

var ranges = ["3-5", "1-4", "0-9", "10-10"];

ranges.sort(function(a, b) {
 return a.split('-')[0] - b.split('-')[0];
});

console.log(ranges);

Output:

["0-9", "1-4", "3-5", "10-10"]