Perl - an array content

Question

Can you explain me how to check if an element belongs to array? My script needs to know whether the element has wanted extension to make a shortcut and copy it to another directory.

Here is an example:

my @array = qw(avi mp4 mov);
my $dir = "E:\Downloads";
opendir (my $dh, $dir);
while (my $file = readdir($dh))
{
    if($file ~= ) 
    instructions...
}

Answer 1

There is a solution in perlfaq4, section "How can I tell whether a certain element is contained in a list or array?" here: http://perldoc.perl.org/perlfaq4.html#How-can-I-tell-whether-a-certain-element-is-contained-in-a-list-or-array ?

If you are using Perl 5.10 or newer, the solution is:

if( $item ~~ @array ) {
    say "The array contains $item"
}

Please have a look at the link if you have an older Perl. There is other possibilities as well.

Regarding you task: if you just want to search a folder for files having a certain extension, I can recommend using File::Find::Rule :

# find all the .pm files in @INC
my @files = File::Find::Rule->file()
                        ->name( qr/\.(?:avi|mp4|mov)$/ )
                        ->in( $dir );

Answer 2

You can use grep to go through the array one at a time and see if any match:

if ( grep $file ~= /\Q.$_\z/, @array ) {

Or join the array elements into a single regex:

my @array = qw(avi mp4 mov);
my $selected_extensions = qr/^\.(?:@{[ join '|', map quotemeta, sort @array ]})\z/;
my $dir = "E:\Downloads";
opendir (my $dh, $dir);
while (my $file = readdir($dh))
{
    if($file ~= $selected_extensions) 
    instructions...
}

Answer 3

In your case you can write

while ( my $file = glob 'E:\Downloads\*.{avi,mp4,mov}' ) {
    # Process $file
}