D wrote:
I ran into something that I need help understanding. In the attached
script, subroutine file_proc1 converts all elements of @molec to
undef, while file_proc2 does not. adjusting file_proc1 to first slurp
the file into an array "fixes it". My best guess (via dum_sub) is
that the subroutine is crossing the $_ from the processing of @molec
and that of the<> operator, but i'd like to know what's happening so
I can avoid this in the future.
$_ is a *global* variable so when the "while (<$input_fh>)" loop ends in
the 'file_proc1' subroutine the value of undef is stored in $_ and that
then affects the contents of @molec in the foreach loop. This is called
"action at a distance" and is why it is recommended that you use
explicit lexical variables like in the 'file_proc2' subroutine and
probably also in the foreach loop, e.g.:
foreach my $element ( @molec ) {
file_proc1( $name_file{ $element } );
}
print Dumper(\@molec);
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
direction. -- Albert Einstein
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