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Full Discussion: Regular Expressions
Top Forums Shell Programming and Scripting Regular Expressions Post 302367478 by durden_tyler on Monday 2nd of November 2009 07:39:20 PM
Old 11-02-2009
Quote:
Originally Posted by DavidHe
...
Hi thank u for your reply. I juz get confused that why ".*\s" does not match "last " Thank you
note that there is a whitespace after double-quoted last
It's pretty simple.

(A) Yes, ".*\s" does match " last ". (i.e. "last" with a space at both ends).
(B) It matched, but was not stored in a variable.

Why not ? Because it was not enclosed within brackets.

If you enclose it within brackets, then $2 will be assigned the value " last ". And, of course, "challenge" will go to $3.

The test is shown below:

Code:
$
$ cat -n tst.pl
     1  #!/usr/bin/perl
     2  $word = "one last challenge";
     3  if ( $word  =~ /^(\w+)(.*\s)(\w+)$/ )
     4  {
     5    print "==>|$1|<==";    # ==>|one|<==
     6    print "\n";
     7    print "==>|$2|<==";    # ==>| last |<==
     8    print "\n";
     9    print "==>|$3|<==";    # ==>|challenge|<==
    10  }
    11
$
$ perl tst.pl
==>|one|<==
==>| last |<==
==>|challenge|<==$
$
$

Note that the value of $2 is "last" with a single space at both ends.
Also note that $3 equals "challenge" without a newline at the end, due to which the $ prompt of the shell shows up right after those "==" characters.

HTH,
tyler_durden
 

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LEARN ABOUT DEBIAN

sql::reservedwords::db2

SQL::ReservedWords::DB2(3pm)				User Contributed Perl Documentation			      SQL::ReservedWords::DB2(3pm)

NAME

       SQL::ReservedWords::DB2 - Reserved SQL words by DB2

SYNOPSIS

	  if ( SQL::ReservedWords::DB2->is_reserved( $word ) ) {
	      print "$word is a reserved DB2 word!";
	  }

DESCRIPTION

       Determine if words are reserved by DB2.

METHODS

       is_reserved( $word )
	   Returns a boolean indicating if $word is reserved by either DB2 5, 6, 7 or 8.

       is_reserved_by_db2v5( $word )
	   Returns a boolean indicating if $word is reserved by DB2 5.

       is_reserved_by_db2v6( $word )
	   Returns a boolean indicating if $word is reserved by DB2 6.

       is_reserved_by_db2v7( $word )
	   Returns a boolean indicating if $word is reserved by DB2 7.

       is_reserved_by_db2v8( $word )
	   Returns a boolean indicating if $word is reserved by DB2 8.

       reserved_by( $word )
	   Returns a list with DB2 versions that reserves $word.

       words
	   Returns a list with all reserved words.

EXPORTS

       Nothing by default. Following subroutines can be exported:

       is_reserved
       is_reserved_by_db2v5
       is_reserved_by_db2v6
       is_reserved_by_db2v7
       is_reserved_by_db2v8
       reserved_by
       words

SEE ALSO

       SQL::ReservedWords

       <http://www-306.ibm.com/software/data/db2/udb/>

AUTHOR

       Christian Hansen "chansen@cpan.org"

COPYRIGHT

       This program is free software, you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.8.8							    2008-03-28					      SQL::ReservedWords::DB2(3pm)
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