|Perl: the Markov chain saw|
Re: trouble with substitutionby kejohm (Hermit)
|on Jan 19, 2012 at 02:45 UTC||Need Help??|
The $ in the regex needs to be escaped (like this: s/ \$VAR1/ my %hash /) so Perl doesn't go looking for a variable named $VAR1 and complain when it can't find it.
Also, you have a subtle error in your code. The line if ($line = ~s/ \$VAR1/ my %hash /) is actually performing the search and replace on the default variable $_ (which hasn't been set to anything), taking the bitwise negation of the result (the number of replacements made, most likely zero) and assigning that result to the $line variable, which will most likely be true and execute the if block. The code should be like this:
In any case, this won't change your input file. You would need to write out to a new file after the search and replace.
A better way to do this is to specify the name of the variable when you dump your data structure using the $Data::Dumper::Varname variable, eg:
An alternative is to use the object-oriented interface. You can specify your own names for your data structures, eg:
See the docs for Data::Dumper for more details.
As an aside, you may want to consider dumping your data in a format such as XML or JSON, instead of as a Perl data structure.
Update: Minor clarifications re syntax.