Quantifier follows nothing in regex

Question

My requirement is to print the files having 'xyz' text in their file names using perl. I tried below and got the following error

Quantifier follows nothing in regex marked by <-- HERE in m/* <-- HERE xyz.xlsx$/;

use strict;
use warnings;

my @files = qw(file_xyz.xlsx,file.xlsx);
my @my_files = grep { /*xyz.xlsx$/ } @files;
for my $file (@my_files) {
    print "The output $file \n";
}

Problem is coming when I add * in grep regular expression. How can I possibly achieve this?

Answer 1

The * is a meta character, called a quantifier. It means "repeat the previous character or character class zero or more times". In your case, it follows nothing, and is therefore a syntax error. What you probably are trying is to match anything, which is .*: Wildcard, followed by a quantifier. However, this is already the default behaviour of a regex match unless it is anchored. So all you need is:

my @my_files = grep { /xyz/ } @files;

You could keep your end of the string anchor xlsx$, but since you have a limited list of file names, that hardly seems necessary. Though you have used qw() wrong, it is not comma separated, it is space separated:

my @files = qw(file_xyz.xlsx file.xlsx);

However, if you should have a larger set of file names, such as one read from a directory, you can place a wildcard string in the middle:

my @my_files = grep { /xyz.*\.xlsx$/i } @files;

Note the use of the /i modifier to match case insensitively. Also note that you must escape . because it is another meta character.