user3425900 user3425900 - 1 year ago 99
Perl Question

Perl Grep Exclusion

I'm grepping values for a list of legitimate file names but there are certain file name matches I'm trying to exclude. I can't quite figure out the exclusions.

List = (

@files = grep(/(?!readme|makefile)([a-z]\.[a-z])/i,@list);

The grep works fine without the exclusion but what am I missing to exclude items matching (readme|makefile) or other patterns?

EDIT: My filenames must include a period (such as, hence the reason for exclusions as opposed to weeding out the unwanted names alone.


It's the "magic regex" again, that's expected to move the earth in a single pattern

It's hard to tell from your question what result you want, but it looks like you want any file that has a dot in its name that doesn't start with readme or makefile

So just write that. After all, that's how .gitignore works: it's just a list of files or file patterns to ignore, it's not one long super-complicated glob expression

This way others, and you yourself in six months' time, will be able to make out what your code does

use strict;
use warnings qw/ all FATAL /;
use feature 'say';

my @list = qw/

my @filtered = grep {
    /\./ and not /^readme/i and not /^makefile/i;
} @list;

say for @filtered;