Negating a perl regexp

Question

my ($INV_NB, $USAGE)=split /\|/,"9998|999999999999999";

if ($USAGE=~/^\d{15}\b/)
{
  print "\nUSAGE is Valid\n";
  print "length of $USAGE is ",length($USAGE);  
}

This worked as expected, but how can I negate this regexp? say if usage is not /^\d{15}\b/

if ($USAGE!=~/^\d{15}\b/)
{
  print "\nUSAGE is Invalid\n";
  print "length of $USAGE is ",length($USAGE);  
}

I tried this, but it isnt working ..

There's `unless (EXPR) BLOCK` too, which *may* make the meaning more obvious. — Mike, Jun 28 '11 at 11:40

Igor · Accepted Answer · 2011-06-28T11:35:05.250

5

You can do:

if ($USAGE !~ /^\d{15}\b/)

Perl documentation:

Binary "!~" is just like "=~" except the return value is negated in the logical sense.

edited Jun 28 '11 at 11:35

answered Jun 28 '11 at 11:29

Igor

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Or you can do `unless ($USAGE=~/^\d{15}\b/)` or `if (not $USAGE=~/^\d{15}\b/)` – Francisco R Jun 28 '11 at 11:39

score 4 · Answer 2 · answered Jun 28 '11 at 11:53

4

The other answers are correct, but if you ever want to negate a regex (and not the operator that applies it), you can use

/^(?!.*?$regex_to_be_negated)/s

answered Jun 28 '11 at 11:53

moritz

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score 0 · Answer 3 · answered Jun 28 '11 at 11:47

0

Also:

unless ($USAGE=~/^\d{15}\b/)
{
  print "\nUSAGE is Invalid\n";
  print "length of $USAGE is ",length($USAGE);  
}

answered Jun 28 '11 at 11:47

dsm

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Negating a perl regexp

3 Answers3