Michael Alipio wrote:
Hi,
Suppose I have this code:
#/usr/local/bin/perl use warnings; use strict; use subs 'verify';
my %where=( Gary => "Dallas", Lucy => "Exeter", Ian => "Reading",
Samantha => "Oregon" );
# Then i open a logfile
open FH, '<', $logfile or die "Can't open $logfile!: $!";
# Now, for every line in the logfile, I will retrive a particular
string, let's say a person's name and verify if it exists in my hash
above:
while (<FH>){ (my $person) = $_ =~ /person=(\S+)/; my $personstatus =
verify(\%where,$person);
# And do anything if the personstatus is this and that.
# Now, on my sub "verify", I would like to know if the person exists
in my hash.
sub verify { my $where = shift @_; my $person = shift @_; my
$personstatus;
if (exists $$where{$person}){
$personstatus =1; }else { $personstatus = 0; }
$personstatus; }
Am I thinking as this is how it should be done when passing hashes to
a subroutine? My program doesn't work and I know it has something to
do with the "my $personstatus" line as well as "if (exists
$$where{$person} line. Can you show me the right way of passing
hashes to subroutines? Thanks.
I also tried declaring %where as 'our' so that I can use "if (exists
%where{$person}" instead of "if(exists $$where{person}) but i still
can't make it work.
Do you know if I am making any sense here?
Thanks
Why pass a reference to the same hash for every line of the <FH>? You
have declared the %where hash at the top so it's already available to
the sub-routine. Much simpler:
while (<FH>) {
my ($person) = $_ =~ /person=(\S+)/; # are you sure this works?
my $personstatus = verify($person);
}
sub verify {
local $_ = shift; # $_ contains $person from while loop
return $where{$_} ? 1 : 0;
}
Or even simpler, dispose of verify() and just do:
while (<FH>){
my ($person) = $_ =~ /person=(\S+)/;
my $personstatus = $where{$person} ? 1 : 0;
}
The correct way to accept a hashref in a sub-routine is:
sub my_subroutine {
my $hashref = shift;
my $something_else = shift;
# OR:
my ($hashref, $something_else) = @_;
}
--
ra(dot)jones(at)dpw(dot)clara(dot)co(dot)uk
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