Simple RegExp Explanation

JavaScript
1

Here’s my code


<html>
<body>

<script type="text/javascript">
    var input    = "id=87654 name=Kenny";
    var regid    = new RegExp("id=([0-9]+)");
    var regname  = new RegExp("name=([a-zA-z]+)");
    
    var id   = regid.exec(input);
    var name = regname.exec(input);
    
    document.write(id);
    document.write("<br>");
    document.write(name);

</script>

</body>
</html>

The output is


id=87654,87654
name=Kenny,Kenny

How can I get the output to be


id=87654
name=Kenny

I basiclly want to assign the integer and string to their own variables, but without the comma and dupe values.

2

Performing regexp.exec returns an array. The 0th item in the array will be text that matches the regular expression. In this case this will be the full “id=87654” and “name=Kenny”. The parentheses are used to delimit the substr matches. In order from left to right these parentheses matches are generally referred to as $1, $2… etc. and they will be in the arrays returned by .exec in items [1], [2], etc. respectively. To reference just the ID and just the name, you want to reference the $1 parentheses match, which is stored in the index 1 element of the array.

See the below code:

<script type="text/javascript">
    var input    = "id=87654 name=Kenny";
    var regid    = new RegExp("id=([0-9]+)");
    var regname  = new RegExp("name=([a-zA-z]+)");
    
    var id   = regid.exec(input);
    var userName = regname.exec(input);
    
    document.write(id[1]);
    document.write("<br>");
    document.write(userName[1]);

</script>

</body>
</html>
3

I also meant to mention that I was getting weird behavior with the var named “name”. Using trusty old google it looks like “name” is potentially a reserved keyword in javascript, so it’s safer to avoid it. (I used userName instead).

4

Thank you, benzittlau. I had a feeling that might have been what it was. I was trying userName.[1], but I see now that the period is not used with arrays.