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2019-09-23T05:05:50Z

initial content

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Perl is a scripting language.

== Basics ==
Since I know PHP, here's the PHP equivalent for some of Perl's constructs.

{|
! PHP Arrays !! Perl Arrays
|-
| {{highlight|lang=php|code=
$a = [];
$a = [ 'x', 'y', 'z' ];
$a = range(1, 100);
$a[] = 'push';
$a = arary_merge('x', $array1, $array2)
$len = count($a)

foreach ($x as $k) {..}

}}
| {{highlight|lang=perl|code=
@a = ();
@a = ( 'x', 'y', 'z' );
@a = 1..100;
$a[@a] = 'push';
@a = ('x', @array1, @array2);
$len = scalar(@a); # or $len = @a

foreach $k (@a) {..}
}}

|-
! PHP Hashes || Perl Hashes
|-
| {{highlight|lang=php|code=
$h = [];
$h = array[
'foo' => 'bar',
'abc' => 'xyz',
];
$h['x'] = 42;

foreach ($h as $key => $value) {..}

$a = array_keys($h);
$b = array_values($h);

$x = isset($h['foo']);

unset($h['x']);
}}
| {{highlight|lang=perl|code=
%h = ();
%h = (
'x' => 'y',
'z' => 'w',
);
$h{'x'} = 42;

while (($key,$value) = each(%h)) {..}

$a = keys(%h);
$b = values(%h);

exists $h{'foo'};

delete $h{'x'};
}}

|-
! PHP Strings || Perl Strings
|-
| {{highlight|lang=php|code=
$s = strtoupper($s);

$s = strtolower($s);

if ($s1 == $s2) {..}

preg_match( "/(\w+)/", $s, $match );
$substr = $match[1];

preg_match_all( "/(\w+)/", $s, $match );
$all = $match[0];

$s = preg_replace( "/\s+/", 'X', $s, 1 );
$s = preg_replace( "/\s+/", 'X', $s );

$s = trim($s);
}}

| {{highlight|lang=perl|code=
$s = lc($s);
$s =~ tr/A-Z/a-z/;
$s = uc($s);
$s =~ tr/a-z/A-Z/;

if $sq eq $s2

$s =~ m/(\w+)/;
$substr = $1;

@all = ($s =~ m/(\w+)/g);

$s =~ s/\s+/X/;
$s =~ s/\s+/X/g;

$s =~ s/^\s+|\s+$//g;
}}

|-
! PHP Environment Variables !! Perl Environment Variables
|-
| {{highlight|lang=php|code=
$_SERVER
$_SERVER['REQUEST_METHOD']
$argv[$i+1]
$argv[0]
}}
| {{highlight|lang=perl|code=
%ENV
$ENV{REQUEST_METHOD}
$ARGV[$i]
$0
}}

|-
! PHP Functions !! Perl Subroutines
|-
| {{highlight|lang=php|code=
function foo() {
}

function foo2($x, $y) {
return $x + y;
}

foo2(10, 20);
}}
| {{highlight|lang=perl|code=
sub foo {
}

sub foo2 {
my ($a, $b) = @_;
return $a + b;
}

foo2(10, 20);
}}

|}

== See Also ==
* https://www.tutorialspoint.com/perl/perl_subroutines.htm
* https://perlmaven.com/subroutines-and-functions-in-perl
* https://www.perltutorial.org/passing-parameters-to-subroutine/

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