Incrementing String by one with Perl

Question

why this perl code increment $v string by 1

 use strict;
    use warnings;

   my $v='AAAAAYAQUypALsDz';

    print ++$v

while the below is not:

use strict;
use warnings;


my $v='AAAAAmGJoD1dlkkt';
    print ++$v

and i get Argument "AAAAAmGJoD1dlkkt" isn't numeric in preincrement (++)

any idea why this happens and how to increment such string by 1 using Perl?

"The auto-increment operator has a little extra builtin magic to it. If you increment a variable that is numeric, or that has ever been used in a numeric context, you get a normal increment. If, however, the variable has been used in only string contexts since it was set, and has a value that is not the empty string and matches the pattern /^[a-zA-Z]*[0-9]*\z/, the increment is done as a string, preserving each character within its range, with carry" The value in $v doesn't match the pattern that activates the "magic" string increment. — ikegami
– ikegami, Commented Jul 17, 2019 at 2:45
Besides, you have a mix of lowercase and uppercase letters in your string, so it doesn't make sense to use ++; it couldn't possibly do what you want (whatever that is). — ikegami
– ikegami, Commented Jul 17, 2019 at 3:25

aod · Accepted Answer · 2019-07-18 01:18:19Z

0

As ikegami mentioned, perl does not interpret the second string as a number. So you could do

use strict;
use warnings;

my $v='AAAAAmGJoD1dlkkt';
my $v = scalar $v;
print ++$v;

Now if you want to add "1" to the end of the string, you should this

$v .= '1';

answered Jul 18, 2019 at 1:18

aod

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