# Get a list of all files in a given directory
# Note use of the grep to exclude subdirectory names
my @files_in_dir = grep { !-d $_ } glob( "myfolder/*" );

# Strip off any leading folder names so that
# myfolder/file1.txt then becomes just file1.txt
s/.*[\\\/]// for @files_in_dir;

##</code><code>##

my @matching_files = grep { $wanted{ $_ } } @files_in_dir;