Ideaz From Ur Brainz

In the following code snippet, 'c' is not as key in 'foo' but is set to {} when the last check for foo->c->0 is called. / tmp ( ) $ cat foo . pl use strict ; use warnings ; use Data : : Dumper ; sub abcde { my $foo = { 'a' = > 1 , 'b' = > 2 } ; print Dumper ( $foo ) ; if ( exists $foo - > { c } & & defined $foo - > { c } - > { 0 } ) { print "C is defined" ; } print Dumper ( $foo ) ; if ( defined $foo - > { c } and defined $foo - > { c } - > { 0 } ) { print "C is defined" ; } print Dumper ( $foo ) ; if ( defined $foo - > { c } - > { 0 } ) { print "C is defined" ; } print Dumper ( $foo ) ; } abcde ( ) ; / tmp ( ) $ perl foo . pl $VAR1 = { 'a' = > 1 , 'b' = > 2 } ; $VAR1 = { 'a' = > 1 , ...

Perl looping of an array with index as well as the item stored in variables, /tmp$ cat loop_with_index.pl  my @arr=(1,2,3,4); while (my ($i, $x) = each(@arr)) {     print "$i: $x\n"; } /tmp$ perl loop_with_index.pl  0: 1 1: 2 2: 3 3: 4

To get the keys of a constant hashref you first need to learn that a constant is actually a function and hence use () to get the keys from it INPUT: $ cat perlConstant.pl use Data::Dumper; use constant FOOHASH => { "foo" => "bar", }; print FOOHASH->{"foo"}."\n"; foreach $key (keys %{FOOHASH()}) { FOOHASH->{$key} = "bar1"; } print FOOHASH->{"foo"}."\n"; foreach $key (keys %{FOOHASH}) { FOOHASH->{$key} = "bar2"; } print FOOHASH->{"foo"}."\n"; OUTPUT: $ perl perlConstant.pl bar bar1 bar1