PERL Beginners - Load hash from a scalar

Author

Load hash from a scalar

Scooter

2008-03-28, 4:13 am

I want to load the value from scalar variable to a hash

Example:
my $a = "a, 1, b, 2, c, 3";

Now, I need to create a hash %b, which holds values like
%b = { a => 1, b => 2, c => 3 };

TIA.

John W. Krahn

2008-03-28, 4:13 am

scooter wrote:
> I want to load the value from scalar variable to a hash
>
> Example:
> my $a = "a, 1, b, 2, c, 3";
>
> Now, I need to create a hash %b, which holds values like
> %b = { a => 1, b => 2, c => 3 };

$ perl -le'
use Data::Dumper;
my $a = "a, 1, b, 2, c, 3";
my %b = $a =~ /[^, ]+/g;
print Dumper \%b;
'
$VAR1 = {
'c' => '3',
'a' => '1',
'b' => '2'
};

John
--
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order. -- Larry Wall

Sanket Vaidya

2008-03-31, 4:42 am

Here is the code to accomplish your task.

use warnings;
use strict;

my $a = "a, 1, b, 2, c, 3";

$a =~ s/ //g; #delete spaces from $a

my @array = split(",",$a);

my %b = (
$array[0] => $array[1],
$array[2] => $array[3],
$array[4] => $array[5]
);

for (keys%b)
{
print "$_ => $b{$_}\n";
}

The output is:

c => 3
a => 1
b => 2

Hope it is useful.

-----Original Message-----
From: scooter [mailto:verma.abhinav@gmail.com]
Sent: Friday, March 28, 2008 12:00 PM
To: beginners@perl.org
Subject: Load hash from a scalar

I want to load the value from scalar variable to a hash

Example:
my $a = "a, 1, b, 2, c, 3";

Now, I need to create a hash %b, which holds values like
%b = { a => 1, b => 2, c => 3 };

TIA.

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John W. Krahn

2008-03-31, 4:43 am

sanket vaidya wrote:
>
>
> Here is the code to accomplish your task.
>
>
> use warnings;
> use strict;
>
> my $a = "a, 1, b, 2, c, 3";
>
> $a =~ s/ //g; #delete spaces from $a

You can do that more efficiently with tr///:

$a =~ tr/ //d; #delete spaces from $a

> my @array = split(",",$a);

Or you can delete the spaces when you split the string:

my @array = split / *, */, $a;

> my %b = (
> $array[0] => $array[1],
> $array[2] => $array[3],
> $array[4] => $array[5]
> );

You can just assign a list directly to a hash:

my %b = @array;

Or just assign the list returned from split:

my %b = split / *, */, $a;

> for (keys%b)
> {
> print "$_ => $b{$_}\n";
> }
>
> The output is:
>
> c => 3
> a => 1
> b => 2

John
--
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order. -- Larry Wall

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