[PerlChina] split function and zero-width seperator
tigerpeng2001 at yahoo.com
Thu Oct 22 19:59:15 PDT 2009
Thank. I thought the seperator would lost. I just read perldoc -f split, which says, "If the PATTERN contains parentheses, additional list elements are created from each matching substring in the delimiter."
From: cnhack TNT <cnhacktnt at gmail.com>
To: china-pm at pm.org
Sent: Thu, October 22, 2009 7:57:37 PM
Subject: Re: [PerlChina] split function and zero-width seperator
perl -MData::Dumper -le '$a="15678.91 ml; r45.12 "; @a=grep !/^\s*$/, split /([\d\.]+)/, $a; print Dumper \@a'
the regex pattern for split don't need to be that complicated. :-)
2009/10/23 tiger peng <tigerpeng2001 at yahoo.com>
>I am trying to isolate numbers from string, manipulate the numbers then put them back to original positions in the string. When I try to use zero-width separator, the split function looks weird, it generated much more elements than I expect.
>Are there any mistakes? Why the split behaviors like this? (The regexp looks right when I used it s///)
>Could anyone help?
>#build the seperator
>:-) perl -le '$a = "15678.91 ml; r45.12 ";
> $a =~ s/((?!(\d|\.))(?<=(\d|\.)))|((?=(\d|\.))(?<!(\d|\.)))/|/g;
> print $a'
>|15678.91| ml; r|45.12|
>#use the seperator in split
>:-) perl -MData::Dumper -le '$a = "15678.91 ml; r45.12 ";
> @a = split /((?!(\d|\.))(?<=(\d|\.)))|((?=(\d|\.))(?<!(\d|\.)))/, $a;
> print Dumper(@a)'
>$VAR1 = '15678.91';
>$VAR2 = '';
>$VAR3 = undef;
>$VAR4 = '1';
>$VAR5 = undef;
>$VAR6 = undef;
>$VAR7 = undef;
>$VAR8 = ' ml; r';
>$VAR9 = undef;
>$VAR10 = undef;
>$VAR11 = undef;
>$VAR12 = '';
>$VAR13 = '4';
>$VAR14 = undef;
>$VAR15 = '45.12';
>$VAR16 = '';
>$VAR17 = undef;
>$VAR18 = '2';
>$VAR19 = undef;
>$VAR20 = undef;
>$VAR21 = undef;
>$VAR22 = ' ';
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