topic how to access elemt in array from perl in Operating System - HP-UX

how to access elemt in array from perl

diwakar_4 — Thu, 30 Jul 2009 10:03:49 GMT

Hi All,

I have one array say:

a=('jan','feb','mar','apr','may','june','jul') ,[(2,4)];

i am not able to compile thsi statment. It gives me the error like:

Can't modify constant item in scalar assignment at af.pl line 2, near "),"
Execution of af.pl aborted due to compilation errors.

And also what is the difference betwenn [] and [()] operatores in accessing the elements.

Thanks

Re: how to access elemt in array from perl

Steven E. Protter — Thu, 30 Jul 2009 10:09:17 GMT

Shalom,

A tutorial:
http://www.comp.leeds.ac.uk/Perl/associative.html

SEP

Re: how to access elemt in array from perl

James R. Ferguson — Thu, 30 Jul 2009 11:01:15 GMT

Hi:

It's not clear exactly what you are trying to do. You need to specify and array with the '@' sigil. Then it appears that you want an array slice of elements 2 and 4. Something like this:

#!/usr/bin/perl
use strict;
use warnings;
my @a=('jan','feb','mar','apr','may','june','jul');
print join ' ', @a[(2,4)], "\n";
my @b=qw( jan feb mar apr may june jul);
print join ' ', @b[2,4], "\n";

...You should use the 'strict' and 'warnings' pragmas as they will expose many errors.

You can drop the inner parentheses from the slice as I show in the second example.

@ SEP: You say you know Perl. You should know then that this was a simple array and not a hash.

Regards!

...JRF...

Re: how to access elemt in array from perl

diwakar_4 — Thu, 30 Jul 2009 11:31:38 GMT

Hi JRF,

Many thanks

Both the outputs are same. It means
@b[2,4]=@b[(2,4)]

If both are same then why () is used, is any specify significance of this?

Thanks

Re: how to access elemt in array from perl

James R. Ferguson — Thu, 30 Jul 2009 11:49:05 GMT

Hi (again):

I don't know of any reason why the parenthesis would have been used. There's nothing to evalulate before the slice is taken.

Regards!

...JRF...

Re: how to access elemt in array from perl

diwakar_4 — Fri, 31 Jul 2009 03:59:42 GMT

Hi James,

Thanks a lot. That is fine for me.

Thanks
Diwakar