GSTIN Validation through condition not working in Perl - regex

Question

I have written Perl code for validating GSTIN Number which is related to India’s tax according to the following rules:
The first two digits represent the state code as per Indian Census 2011. Every state has a unique code.
The next ten digits will be the PAN number of the taxpayer
The thirteenth digit will be assigned based on the number of registration within a state
The fourteenth digit will be Z by default
The last digit will be for check code. It may be an alphabet or a number.
Following is the code:
my $gst_number_input = '35AABCS1429B1AX';
my $gst_number_character_count = length($gst_number_input);
my $gst_validation =~ /\d{2}[A-Z]{5}\d{4}[A-Z]{1}[A-Z\d]{1}[Z]{1}[A-Z\d]{1}/;
if ($gst_number_character_count == 15 && $gst_number_input =~ $gst_validation) {
print "GST Number is valid";
} else {
print "Invalid GST Number";
}
I have an invalid GSTIN input entered in the code. So when I run the script, I get:
GST Number is valid
Instead I should get the error because the GSTIN input is invalid:
Invalid GST Number
Can anyone please help ?
Thanks in advance

Answer 1

In this part you are using =~ where is should be an equals sign =
my $gst_validation =~ /\d{2}[A-Z]{5}\d{4}[A-Z]{1}[A-Z\d]{1}[Z]{1}[A-Z\d]{1}/;
If you want to use is as a variable, you could use qr
Note that you can omit {1} from the pattern and you don't have to use the square brackets around [Z]
You code might look like
my $gst_number_input = '35AABCS1429B1AX';
my $gst_number_character_count = length($gst_number_input);
my $gst_validation = qr/\d{2}[A-Z]{5}\d{4}[A-Z][A-Z\d]Z[A-Z\d]/;
if ($gst_number_character_count == 15 && $gst_number_input =~ $gst_validation) {
print "GST Number is valid";
} else {
print "Invalid GST Number";
}