|P is for Practical|
$pi = split('\t', $PAR1_info);
Split returns an array. When you assign an array to a scalar, the array is evaluated in a scalar context and an array evaluated in a scalar context gives the number of elements in the array, not the first element of the array.
There are, as usual with Perl, several ways to get the first element. Here are a couple:my ($pi) = split(/\t/, $PAR1_info); my $pi = (split(/\t/, $PAR1_info);
Note also that split takes a regular expression (pattern) as its first argument, not a string.
Edit: Some days I should stay away from my keyboard....
As dave_the_m points out, what I said about split returning an array is incorrect. In fact (as is generally the case with functions) what split does depends on the context in which it is evaluated. Split does various things differently when evaluated in scalar context rather than list or void context. Of relevance here, from split:
Splits the string EXPR into a list of strings and returns the list in list context, or the size of the list in scalar context.
And, while split is documented to take a pattern, that pattern can be a string.