Re: Another RegExp question

The regex /\d{3}/ matches 3 digits anywhere in the string. If you want to restrict it to only 3 digits, you'd need to anchor it (specify either (both in this case) "start of the string" and the "end of the string" — these are logical atomic units):

if ($step =~ /^\d{3}$/) {
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Update: YAPE::Regex::Explain gives the following explanation:

The regular expression:

(?-imsx:^\d{3}$)

matches as follows:
  
NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  ^                        the beginning of the string
----------------------------------------------------------------------
  \d{3}                    digits (0-9) (3 times)
----------------------------------------------------------------------
  $                        before an optional \n, and the end of the
                           string
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------
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davis

Kids, you tried your hardest, and you failed miserably. The lesson is: Never try.

Edited: Fixed slightly mixed tense.

Comment on Re: Another RegExp question Select or Download Code

Replies are listed 'Best First'.
Re^2: Another RegExp question by Ronnie (Scribe) on Aug 17, 2006 at 11:32 UTC
Thanks for that - guess who's feeling a tad foolish at the moment?!	[reply]
Re^3: Another RegExp question by cdarke (Prior) on Aug 17, 2006 at 11:54 UTC
Don't - it is a common mistake.	[reply]