Using RegEx to extract number from alphanumeric string

Question

I need to identify substring 'X.123' and/or 'X.8' in a longer string of alphanumeric data. Ex:

A cow flew over the moon in the X.123 module, not the X.124.3 module, 
and certainly not the X.125C78 module.  The cow poo-pooed the X.8 module.

How would I exclude the second and third instance? This is what I've come up with so far to get the "X.123" part:

/[X][\.][0-9]{1,4}/

I'm not exactly sure how to make the expression stop at any non-numeric character (ex: X124C78)

Help greatly appreciated!

rand0m · Accepted Answer · 2011-11-12 20:17:26Z

4

The \b is nice in this context, i would use it like this:

/\bX\.\d{1,4}\b/

answered Nov 12, 2011 at 20:17

rand0m

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Regexident · Accepted Answer · 2011-11-12 19:38:07Z

2

Try this:

/X\.[0-9]{1,4}(?=\s|$)/

answered Nov 12, 2011 at 19:38

Regexident

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FailedDev · Accepted Answer · 2011-11-14 21:14:20Z

1

I would use this. The \b in the start helps avoiding matches such as AX.123

/\bX\.\d+(?=\s|$)/

preg_match_all('/\bX\.\d+(?=\s|$)/', $subject, $result, PREG_PATTERN_ORDER);
for ($i = 0; $i < count($result[0]); $i++) {
    # Matched text = $result[0][$i];
}

edited Nov 14, 2011 at 21:14

answered Nov 12, 2011 at 19:55

FailedDev

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