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Re^2: Search array of file names in directory structure

by Anonymous Monk
on Oct 02, 2012 at 15:41 UTC ( #996873=note: print w/ replies, xml ) Need Help??


in reply to Re: Search array of file names in directory structure
in thread Search array of file names in directory structure

Hi, can you explain the Reg. Expression from this line?

my $regex = join '|', map "\Q$_\E?", @filelist;

If you need to look for a particular pattern how would you alter this code; "\Q$_\E?"


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Re^3: Search array of file names in directory structure
by Kenosis (Priest) on Oct 02, 2012 at 16:05 UTC

    Here's the line, explained a bit:

    my $regex = join '|', map "\Q$_\E?", @filelist; ^ ^ ^ ^^ | | | || | | | |+ - Last character in file name optio +nal, i.e., the "l" in html | | | + - End quote metacharacters | | + - The default scalar aliased to each @ +filelist element | + - Begin quote metacharacters (e.g., the +period) + - Join each element with alternation ("or") charac +ter

    As shown, this results in the following:

    1234567_3a_20101000\.html?|99877_b_20111111\.html?|99877_c_20111111\.h +tml? ...

    This line builds a regex using the file names in @filelist. When passed to File::Find::Rule as the -name rule, only those files names which match the regex will be returned by File::Find::Rule, if any.

    If you want File::Find::Rule to look for a particular pattern, change the regex here:

    ->name(qr/^(?:$regex)$/) ^^^^^^^^^^^^

    However, if you want to process the files returned by File::Find::Rule, you can do something like this:

    my @matchingFileNames = grep /pattern/, @found_html;

    where "pattern" represents the regex that would 'filter' the elements of @found_html.

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