Comparing text containing numbers

Question

I have two variables, both containing text and numbers and I'm getting the wrong result when comparing them:

var x = "test_8"
var y = "test_11"
if(x > y){
    alert(x+" is greater than "+y);
}
else{
    alert(y+" is greater than or equal to "+x);
}

I get the alert saying test_8 is greater than test_11 but I should be getting the other alert. I'm guessing I would have to extract the 8 and 11 out as numbers but I'm not sure how to do that.

not sure whether to close as a duplicate or not, but you'll find your solution at [Sort Array Elements (string with numbers), natural sort](http://stackoverflow.com/q/15478954/1048572) which details a fitting comparison function — Bergi, Dec 21 '15 at 12:30
You should provide a bit more detail here. Do you always expect strings of the form `test_X`, where `X` is a number? What exactly is your use case? — Cedric Reichenbach, Dec 21 '15 at 12:31
Yeah I assume its something to do with comparing text when it should be comparing both text and numbers — NiallMitch14, Dec 21 '15 at 12:31
Check http://stackoverflow.com/questions/1862130/strip-non-numeric-characters-from-string — Batu.Khan, Dec 21 '15 at 12:31

score 1 · Accepted Answer · answered Dec 21 '15 at 12:41

1

It need to be converted to number for exact comparison.

    function getNum(str) {
        // it removes all non numeric, but regex can be differ according the str data which uses.
        return Number(str.replace(/\D+/,""));
    }

    var x = "test_8";
    var y = "test_11";

    if(getNum(x) > getNum(y)){
        alert(x+" greater than "+y);
    }
    else{
        alert(y+" greater than "+x);
    }

answered Dec 21 '15 at 12:41

Jae Sung Park

900
6
9

thanks, this was the way I got it fixed. I check if the variable has a number in it and convert it to a number if it does – NiallMitch14 Dec 21 '15 at 13:05

Comparing text containing numbers

1 Answers1