Incrementing an integer at the end of a string in perl

Question

I have a string in the following format:

\main\stream\foo.h\3

it may have more or less "sections", but will always end with a slash followed by an integer. Other examples include:

\main\stream2309\stream222\foo.c\45

\main\foo.c\9

I need to, in Perl, increment the number at the end of the string and leave the rest alone. I found an example on this site that does exactly what I want to do (see Increment a number in a string in with regex) only the language is Javascript. The solution given was:

.replace(/\d+$/,function(n) { return ++n })

I need to do the same thing in Perl.

friedo · Accepted Answer · 2010-07-19 19:49:06Z

11

You can use the /e regex modifier to put executable code in your replacement string.

Something like:

$string =~ s/(\d+)$/$1 + 1/e;

should work.

answered Jul 19, 2010 at 19:49

friedo

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1 Comment

Greg Bacon Over a year ago

Too bad auto-increment is limited to strings that match /^[a-zA-Z]*[0-9]*\z/

friedo · Accepted Answer · 2010-07-19 23:59:56Z

2

Try $var =~ s/(\d+$)/($1 + 1)/e

edited Jul 19, 2010 at 23:59

friedo

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answered Jul 19, 2010 at 19:50

James O'Sullivan

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Comments

chrispitude · Accepted Answer · 2023-03-16 16:03:14Z

0

If you want an underscored suffix and the original string might not have a suffix:

value
value_1
value_2
...

you can use this:

$foo =~ s{_?(\d*)$}{'_'.($1 eq '' ? 1 : $1+1)}e

answered Mar 16, 2023 at 16:03

chrispitude

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