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Old 07-06-2004, 11:01 AM   #1
Registered: Jul 2002
Distribution: Slackware 10.0
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perl simple regexp

Hi....have a very simple reg exp, but I cant get it to work as I want.

my $digit = 12;

if ($digit =~ /\d/) {
  print ("match\n");
} else {
  print ("not match\n");

This prints match, although it should'nt cuz I have 2 digits. But if I change it to \d\d\d, it prints
not match. As it should. The point is that I want to match exactly 1 digit, not 1 or more.

Not sure whats wrong. Any ideas?
Old 07-06-2004, 12:21 PM   #2
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try if( $digit =~ /^\d$/ )
Old 07-06-2004, 12:28 PM   #3
Registered: Apr 2004
Location: Minneapolis
Distribution: Ubuntu
Posts: 45

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There are many ways to solve this problem, all of which are covered in the Perl Regular Expressions documentation.

# match exactly one digit somewhere in string
$digit =~ m/\d{1}/;

# entire string must consist of one digit
$digit =~ m/^\d$/;

# match one digit with non-digits on either side
$digit =~ m/\D\d\D/;
Hope this helps,
-Adam Monsen
Old 07-07-2004, 03:27 AM   #4
Registered: Jul 2002
Distribution: Slackware 10.0
Posts: 46

Original Poster
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thanks to both of you....I had to add the ^ and $, and it worked.


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