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

Accepted Answer

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.

Quantifier follows nothing in regex

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