a reference to an element of an array or hash, how to create?

[S P Arif Sahari Wibowo]

Hi!

Do you know how to create a reference to an element of an array
or hash? For instance I have an array @a, and I like $a2r
contains a reference to $a[2]. Anyway to do it in perl?

Keep in mind this is not the case where $a[2] contain a
reference and $a2r contains the same reference, but instead $a2r
contain a reference to the scalar stored in $a[2].

Let me explain more using the pseudo code below, RefTo represent
the mechanism in question:

my @a= (1, 2, 3, 4);

my $p= RefTo $a[2];

$$p= 9;

print join(",", @a) # should print 1,2,9,4


So, any idea wether there is such mechanism as RefTo in Perl?

Thanks!

 

[xhoster]

Hi!

Do you know how to create a reference to an element of an array
or hash? For instance I have an array @a, and I like $a2r
contains a reference to $a[2]. Anyway to do it in perl?

The Perl "reference to" operator is the backslash.

my @a= (1, 2, 3, 4);

my $p= RefTo $a[2];

$$p= 9;

print join(",", @a) # should print 1,2,9,4

perl -le 'my @x=(1..4); my $p=\$x[2]; $$p=9; print "@x"'
1 2 9 4

Xho

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[John W. Krahn]

Do you know how to create a reference to an element of an array or hash?
For instance I have an array @a, and I like $a2r contains a reference to
$a[2]. Anyway to do it in perl?

Keep in mind this is not the case where $a[2] contain a reference and
$a2r contains the same reference, but instead $a2r contain a reference
to the scalar stored in $a[2].

Let me explain more using the pseudo code below, RefTo represent the
mechanism in question:

my @a= (1, 2, 3, 4);

my $p= RefTo $a[2];

$$p= 9;

print join(",", @a) # should print 1,2,9,4

$ perl -le'my @a = ( 1, 2, 3, 4 ); my $p = \$a[ 2 ]; $$p = 9; print join
",", @a'
1,2,9,4



John

 

[Zak B. Elep]

Do you know how to create a reference to an element of an array or hash?
For instance I have an array @a, and I like $a2r contains a reference to
$a[2]. Anyway to do it in perl?

,----[ perl -de 0 ]
| alteran:~ zakame$ perl -de 0
|
| Loading DB routines from perl5db.pl version 1.28
| Editor support available.
|
| Enter h or `h h' for help, or `man perldebug' for more help.
|
| main:-e:1): 0
| DB<1> @a = ( 1, 2, 3 )
|
| DB<2> $a2r = \$a[2]
|
| DB<3> x $a2r
| 0 SCALAR(0x190fe24)
| -> 3
| DB<4> x $$a2r
| 0 3
`----

 

[S P Arif Sahari Wibowo]

perl -le 'my @x=(1..4); my $p=\$x[2]; $$p=9; print "@x"'

$ perl -le'my @a = ( 1, 2, 3, 4 ); my $p = \$a[ 2 ]; $$p = 9; print join ",", @a'

Duh! I should try it first, didn't think it will be that easy
before.

Thanks everyone!