Question

I have the following variable which is the selected text of a select box. This is the select box markup.

<select name="SELECT___100E___7">
<option selected="" value="25">Beige/Almond</option>
<option value="21">Blue [Subtract -$1.00]</option>
<option value="27">Chrome [Subtract -$2.00]</option>
<option value="29">Red [Add $1.00]</option>
</select>

Variable test_var hold the selected text…

$('select[name^="SELECT___"]').change(function(){
var test_var = $(this).find("option:selected").text();
});

So what I would like to do is remove all characters except for the amount, also removing the “$”. So if “Red [Add $1.00]” is selected I want to have test_var equal to 1.00

Having trouble figuring out the regexp to do this.

Answer 1

This should do it (er, actually, see the update below):

var m = test_var.match(/(-?)\$([0-9\.]+)/);
var result = m.length > 0 ? m[1] : "";

Live example

What that says is “look for a $ followed by a series of digits and . characters, and grab as many of that series as you can when matching.” The resulting match array will have the complete matching string (including the $ in position 0, and then the first (and only) capture group at position 1 — and so we grab that.

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Update Er, um, if you need to capture the - sign (and I’m guessing you do), change that to this:

  var m = test_var.match(/(-?)\$([0-9\.]+)/);
  var result = m.length > 0 ? m[1] + m[2] : "";

Live example

That uses an optional capture for the - if it’s present before the $, and then combines the two capture groups (m[1] and m[2]; m[1] will be “” if there’s no -).

Results (for example):

Red [Add $1.00]        => 1.00
Blue [Subtract -$1.00] => -1.00

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Off-topic: Beware localization! Because in some locales, those .s will be ,s, e.g., “€1,00” for one Euro in Germany.