grep question

darrengan has asked for the wisdom of the Perl Monks concerning the following question:

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Re: grep question by monarch (Priest) on Nov 17, 2005 at 05:31 UTC
If you had an array of file names, and did the following: `my @grepped = grep /\d{8}\.txt$/ @filenames;` [download] ..then your array `@grepped` would contain the entry `'file1_system_051117123050.txt'` if this filename was in the `@filenames` array. However, if you want to capture text from a string, then you want a regular expression match: `if ( $filename =~ m/(\d{4})\d{4}.txt$/ ) { print( $1 . "\n" ); }` [download] ..if `$filename` contained `'file1_system_051117123050.txt'` then you would have `'1712'` printed out as that was the four digits captured within parenthesis (curly brackets) in the regular expression match.	[reply] [d/l] [select]
Re: grep question by murugu (Curate) on Nov 17, 2005 at 05:54 UTC
Hi darrengan, If you have a single filename then, `my ($match)=$file=~/(\d{4})\d{4}\.txt/;` [download] If you have multiple filenames and you want to construct array of the results then, `my @a = map {/(\d{4})\d{4}\.txt/} @filenamearray;` [download] Regards, Murugesan Kandasamy use perl for(;;);	[reply] [d/l] [select]
Re: grep question by Roger (Parson) on Nov 17, 2005 at 05:42 UTC
I'd say something like this would work... `my @capture = map { /(\d{4})\d{4}.txt/ } grep { ... } ...;` [download]	[reply] [d/l]
Re: grep question by kulls (Hermit) on Nov 17, 2005 at 06:09 UTC
I guess you are concatenating timestamp with your file name.if so then, you can create a ( `Time::piece` ) object using `strptime()` function in this module.So that you can get the data from the object directly.Otherwise please tell me, how you generate this numbers, let we try that side also. more info for Time::piece -kulls.	[reply] [d/l] [select]
Re: grep question by l.frankline (Hermit) on Nov 17, 2005 at 06:01 UTC
Hi, Try this.... `$_= 'file1_system_051117123050.txt';` `($_) = grep s/.(\d{4})\d{4}\.txt/$1/, $_;` `print $_;` Regards Franklin Don't put off till tomorrow, what you can do today.*	[reply] [d/l] [select]