I have a string "RowNumber5", now i want to get the numeric value "5" from that string using Javascript.

Note: Numeric value will be always at the end, after alphabets, that means numeric value will never occur in between alphabets. Example -

 Result45 - Yes
 Result45Abc - Never

I can get this "5" by some thing like this

var t = "Ruby12";
var y = parseInt(t.split('').reverse().join(""));
if(!isNaN(y)) {
    y = y.toString().split('').reverse().join("");
}
else {
    y = "";
}
console.log(y);

Any shot way? or Better approach for this ?

I have a string "RowNumber5", now i want to get the numeric value "5" from that string using Javascript.

Note: Numeric value will be always at the end, after alphabets, that means numeric value will never occur in between alphabets. Example -

 Result45 - Yes
 Result45Abc - Never

I can get this "5" by some thing like this

var t = "Ruby12";
var y = parseInt(t.split('').reverse().join(""));
if(!isNaN(y)) {
    y = y.toString().split('').reverse().join("");
}
else {
    y = "";
}
console.log(y);

Any shot way? or Better approach for this ?

• javascript
• string

• This won't work? /.*([0-9]+)$/ – MightyPork Commented Aug 5, 2013 at 12:29
• do you always know the alpha part of that string? if so, you can replace that substring with '' and parseInt the rest – Kuro Commented Aug 5, 2013 at 12:30
• @Kuro: No the alpha part is dynamic. – Ashis Kumar Commented Aug 5, 2013 at 12:42
• @MightyPork: Can you show the full implementation. – Ashis Kumar Commented Aug 5, 2013 at 12:43
• I did now, check the answer – MightyPork Commented Aug 5, 2013 at 12:51

4 Answers 4

This is what regexes were made for!

var matches = /\d+$/.exec("Ruby12");
matches[0];  //returns 12

var matches = /\d+$/.exec("sfwfewcsd098");
matches[0];  //returns 098

var matches = /\d+$/.exec("abc"); //matches returns null

Here's a regex solution:

// input string
var t = "Ruby12";

var num = null;    
var match = t.match(/([0-9]+)$/);    
if(match!=null) num = parseInt(match[1]);

// num now contains null or number

// debug
console.log(num);

Try using this regular expression

var s = "gdgdfg45";
var matches = s.match(/\d+$/);
console.log(matches[0]);

I would go with the divide and conquer method, working through all strings that may contain numbers:

var t = "Ruby12";
function get_numbers(str) {
    var parts = str.split(""), nums = "";
    for(var i = 0, len = parts.length; i < len; i++) {
        nums += (isNaN(parts[i])) ? "" : parts[i].toString();
    }
    return(nums);
}

var numbers = get_numbers(t);
alert(numbers);

Which would give you "12".