PERL Beginners - how to accept array elments using loop

Author

how to accept array elments using loop

lumadhu@gmail.com

2007-12-28, 8:00 am

Hi all,
I am new user of this group. can you tell how can i accept
array elements using loop. for example
for($i=0;$i<5;$i++)
{
$a[$i]=<stdin>;
}

Jeff Pang

2007-12-28, 8:00 am

On Dec 28, 2007 7:42 PM, <lumadhu@gmail.com> wrote:
> Hi all,
> I am new user of this group. can you tell how can i accept
> array elements using loop. for example
> for($i=0;$i<5;$i++)
> {
> $a[$i]=<stdin>;
> }
>

use strict;

my @arr;

while(<> ) {
chomp;
push @arr,$_;
}

Paul Lalli

2007-12-28, 7:01 pm

On Dec 28, 6:42=A0am, luma...@gmail.com wrote:

> =A0 =A0 =A0 =A0 =A0 =A0I am new user of this group. can you tell how can i=
accept
> array elements using loop. for example
> for($i=3D0;$i<5;$i++)
> {
> =A0 $a[$i]=3D<stdin>;
> }

What, exactly, is wrong with the solution you provided right there?
How does it not meet your needs? What do you want to do instead of
that?

Paul Lalli

John W. Krahn

2007-12-28, 7:01 pm

lumadhu@gmail.com wrote:
> Hi all,

Hello,

> I am new user of this group. can you tell how can i accept
> array elements using loop. for example
> for($i=0;$i<5;$i++)
> {
> $a[$i]=<stdin>;
> }

my @a = map scalar <STDIN>, 1 .. 5;

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

Chas. Owens

2007-12-28, 7:01 pm

On Dec 28, 2007 6:42 AM, <lumadhu@gmail.com> wrote:
> Hi all,
> I am new user of this group. can you tell how can i accept
> array elements using loop. for example
> for($i=0;$i<5;$i++)
> {
> $a[$i]=<stdin>;
> }

While this does appear to be valid syntax (except that it is STDIN not
stdin), it is more Perlish to say

for (1 .. 5) {
push @a, scalar <STDIN>;
}

or better yet, since STDIN is the file* that is read from when you
used just use <>

for (1 .. 5) {
push @a, scalar <>;
}

and while we are at it we can use the conditional form of the for loop

push @a, scalar <> for 1 .. 5;

We could also say

my @a = map { scalar <> } 1 .. 5;

if we wanted to initialize @a when we declare it.

Of course, all of this is moot if @a already has data in it and you
want to replace the first five items. In that case you should use
splice:

splice @a, 0, 5, map { scalar <> } 1 .. 5;

* <> has a little bit of magic to it, it will read from STDIN if there
is nothing in @ARGV, but if there are items in @ARGV it will try to
open and read from them instead. This is often the behavior you
desire (see grep, tr, or any of the other filtering UNIX commands).

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