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Re: RFC - Regular Expressions Tutorial, the Basics (for BEGINNERS)

by Not_a_Number (Parson)
on Jan 22, 2007 at 19:43 UTC ( #595976=note: print w/ replies, xml ) Need Help??


in reply to Regular Expressions Tutorial, the Basics (for BEGINNERS)

If we wanted to match a single character, our pattern would be /a./. The control character is a '.' after the letter in question.

No! /a./ means match two characters, an 'a' followed by any other character. To match a single lower-case 'a', the pattern is simply /a/ - try it and see:

$_ = 'He lives in Liberia'; print 'with dot: ', $_ if /a./; # No output print 'without dot: ', $_ if /a/; # Outputs 'without dot: He lives in Liberia'

Also, in your last paragraph, you've inverted your square brackets and slashes...

Update:

To clarify, the dot (period) is not a 'control character', as you seem to imagine, but a 'wildcard character'. To quote from perlretut (which I highly recommend you read, and include in your list of other sources):

The period '.' matches any character but "\n"

Update2: s/perlreftut/perlretut, sorry!


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