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Regular Expressions

L1

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RegEx1.pl
#!/usr/bin/env perl
use utf8;
use English;
use Utils;
use strict;
use warnings;

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	my $s = "Four score and seven years ago...";
	print "Match 1: ", $s =~ qr/s.*e/, "\n";
	print "Match 2: ", $s =~ qr/\bs.*e\b/, "\n";
	print "Match 3: ", $s =~ qr/s...e/, "\n";
	print "Match 4: ", $s =~ qr/b.d/, "\n";

	my $subgroups = [$s =~ qr/((\w+)\s*(\w+))/];
	print "Find First (with subgroups): ", Utils::listToString($subgroups), "\n";
	$subgroups = [$s =~ qr/bad match/];
	print "Find First (bad match): ", Utils::listToString($subgroups), "\n";

	my $matches = [$s =~ m/\w+/g];
	print "Find All: (matches only)", Utils::listToString($matches), "\n";
	$matches = [$s =~ m/bad match/g];
	print "Find All (bad match): ", Utils::listToString($matches), "\n";
}
Output
$ perl RegEx1.pl Match 1: 1 Match 2: 1 Match 3: 1 Match 4: Find First (with subgroups): [Four score, Four, score] Find First (bad match): [] Find All: (matches only)[Four, score, and, seven, years, ago] Find All (bad match): []
RegEx2.pl
#!/usr/bin/env perl
use utf8;
use Utils;
use strict;
use warnings;

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	my $s = "Four score and seven years ago...";
	print "Replace First 1: ", $s =~ s/\.\.\./!!!/r, "\n";
	print "Replace First 2: ", $s =~ s/\b...\b/???/r, "\n";
	print "Replace First 3: ", $s =~ s/b.d/???/r, "\n";
	print "Replace First 4: ", $s =~ s/(\w+) (\w+)/$2 $1/r, "\n";

	print "Replace All 1: ", $s =~ s/\b...\b/???/gr, "\n";
	print "Replace All 2: ", $s =~ s/(\w+) (\w+)/$2 $1/gr, "\n";
}
Output
$ perl RegEx2.pl Replace First 1: Four score and seven years ago!!! Replace First 2: Four score ??? seven years ago... Replace First 3: Four score and seven years ago... Replace First 4: score Four and seven years ago... Replace All 1: Four score ??? seven years ???... Replace All 2: score Four seven and ago years...
RegEx3.pl
#!/usr/bin/env perl
use utf8;
use Utils;
use strict;
use warnings;

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	my $str = "Four score and seven years ago...";
	print "Split 1: ", Utils::listToString([split(qr/ /, $str)]), "\n";
	print "Split 2: ", Utils::listToString([split(qr/[eo]/, $str)]), "\n";
	print "Split 3: ", Utils::listToString([split(qr/\s/, $str)]), "\n";
	print "Split 4: ", Utils::listToString([split(qr/\W/, $str)]), "\n";
}
Output
$ perl RegEx3.pl Split 1: [Four, score, and, seven, years, ago...] Split 2: [F, ur sc, r, and s, v, n y, ars ag, ...] Split 3: [Four, score, and, seven, years, ago...] Split 4: [Four, score, and, seven, years, ago]
perl

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