Creating array of file names using grep - arrays

Question

I'm having difficulty outputting file names as an array using grep. Specifically, I want to create an array of file names (plant photos) formatted like this:
Ilex_verticillata= Ilex_verticillata1.png, Ilex_verticillata2.png, Ilex_verticillata3.png
Asarum_canadense= Asarum_canadense1.png, Asarum_canadense2.png
Ageratina_altissi= Ageratina_altissi1.png, Ageratina_altissi2.png
Here's my original Perl script that I'm attempting to modify. It returns, as intended, ONE file name per plant as "Genus_species", printing a list of those plants:
#!/usr/bin/perl
use strict;
use warnings;
my $dir = '/Users/jdm/Desktop/xampp/htdocs/cnc/images/plants';
opendir my $dfh, $dir or die "Can't open $dir: $!";
my #files =
map { s/1\.png\z/.png/r } # Removes "1" from end of file names
grep { /^[^2-9]*\.png\z/i && /_/ } # Finds "Genus_species.png" & "Genus_species1.png" and returns one file name per plant as "Genus_species.png"
readdir $dfh;
foreach my$file (#files) {
$file =~s/\.png//; # Removes ".png" extension
print "$file\n"; #Prints list of file names (plant names)
}
Here's the output:
Ilex_verticillata
Asarum_canadense
Ageratina_altissima
However, since each plant often has MULTIPLE photos (e.g.-- "Genus_species1.png, Genus_species2.png, etc.), I need to re-grep the directory using the above output to find their file names, then output the results in the form of an array as previously illustrated.
I know the solution likely involves modifying the "foreach" statement, using grep to return ALL file names with "Genus_species" in their name. Here's what I tried:
foreach my$file (#files) {
$file =~s/\.png//;
grep ($file,readdir(DIR));
print "$file = $file\n";
But the output was this:
Ilex_verticillata = Ilex_verticillata
Asarum_canadense = Asarum_canadense
Ageratina_altissima = Ageratina_altissima
Again, I want to output an array formatted as:
"Genus_species= Genus_species1.png, Genus_species2.png, etc.," meaning I want it to look like this:
Ilex_verticillata= Ilex_verticillata1.png, Ilex_verticillata2.png, Ilex_verticillata3.png
Asarum_canadense= Asarum_canadense1.png, Asarum_canadense2.png
Ageratina_altissi= Ageratina_altissi1.png, Ageratina_altissi2.png
Notice that I also want to add back the ".png" extension ONLY to the file names to the right of the equals sign.
Please advise. Thanks.

Answer 1

Readdir returns a list of files in the folder. You've put them on one line, which is compact. However, if you loop them you can process the items further.
#!/usr/bin/perl
use strict;
use warnings;
use English; ## use names rather than symbols for special varables
my $dir = '/Users/jdm/Desktop/xampp/htdocs/cnc/images/plants';
opendir my $dfh, $dir or die "Can't open $dir: $OS_ERROR";
my %genus_species; ## store matching entries in a hash
for my $file (readdir $dfh)
{
next unless $file =~ /\d\.png$/; ## skip entry if not a png file ending with a number
my $genus = $file =~ s/\d\.png$//r;
push(#{$genus_species{$genus}}, $file); ## push to array,the #{} is to cast the single entry to a referance to an list
}
for my $genus (keys %genus_species)
{
print "$genus = ";
print "$_ " for sort #{$genus_species{$genus}}; # sort and loop though entries in list referance
print "\n";
}