Re: Validating Hex Numbers


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Re: Validating Hex Numbers

by PodMaster (Abbot)

on Jan 08, 2003 at 22:36 UTC ( [id://225380]=note: print w/replies, xml )

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in reply to Validating Hex Numbers

That won't really validate the number.

Feed it any of these non-hex strings and they'll be validated.

qw[
   afg
   fA
   lA
   rA
   0X
]
[download]

and the list goes on.

You need to make sure the entire string consists of only those characters, and in order to do that, you need anchors (notice I use \z instead of $)

/^[\da-f]+\z/i
[download]

The other thing you might have to check is the length of the string (should be even, even though 'AFF' might be considered '0AFF', whatever).

update: thanks sauoq for tyepo catch ;)

MJD says you can't just make shit up and expect the computer to know what you mean, retardo!
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Re: Re: Validating Hex Numbers
by seattlejohn (Deacon) on Jan 09, 2003 at 01:11 UTC

A

8

Of course, in computing contexts single-hex-digit numbers are unusual, but the poster didn't specify what the source or destination of this data is, so I wouldn't want to build in that assumption without additional information.

One thing that the post implies but doesn't make explicit is that "number" really means "non-negative integer". If you want to be truly comprehensive, something like -A8F.C is a valid hex number (namely -2073.75 decimal), but not something most of us likely encounter on a regular basis.

$perlmonks{seattlejohn} = 'John Clyman';

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