Exclude a pattern in RegEx

Question

I want a RegEx to match any Hex number but 7E and 7D.

To match any Hex number I use [0-9A-F]{2}. How can I now exclude the unwandted numbers?

Most engines or programs have some kind of 'not' function that is mostly much more effective than regexp that matches everything 'but'. I'd suggest you to look that way first, then use complex things as desc. in answers. — Tomas Pruzina
– Tomas Pruzina, Commented Mar 15, 2012 at 17:03

Ahmad Mageed · Accepted Answer · 2012-03-15 16:59:07Z

1

You could use a negative look-ahead that would fail on 7E or 7D. The following pattern uses ^ and $ to match the entire string, not a partial match within a string.

^(?!7[ED])[0-9A-F]{2}$

answered Mar 15, 2012 at 16:59

Ahmad Mageed

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woodtluk Over a year ago

Thanks this worked. I don't need the '^' and '$' since I use the RegEx as terminal in a parser generated with TinyPG.

Pooria Azimi · Accepted Answer · 2012-03-15 16:51:51Z

0

You could use something like this:

[0-68-F][0-F] || 7[0-CF]

(the || might not work, depending on where you're using this regex. You didn't specify that in your question)

answered Mar 15, 2012 at 16:51

Pooria Azimi

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Comments

Alex · Accepted Answer · 2012-03-15 16:53:45Z

0

[0-9A-F&&[^7]][0-9A-F&&[^DE]]

answered Mar 15, 2012 at 16:53

Alex

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woodtluk Over a year ago

Id didn't work. I think that would ignore any Hex Number that has the fist digit 7 and the second digit D od E.

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