a simple question

[Raghavendra Mahuli]

Hi all,
I have a simple question in perl... I have an array -

@a = (10,20,30,40);

Since '$' gives the scalar of a array , i expect "print $a" to give the no.
of elements in the array...
But it dosent work.. However if i copy it to a scalar and then print it, it
works.. Can u pls explain why it is so?
Here is the program listing:

@a = (10,20,30,40);
$x= @a;
print $a;
print $x;

thanx in advance,
regards,
raghu

 

[Brian McCauley]

Subject: a simple question

Please put the subect of your post in the Subject of your post.

Hi all,
I have a simple question in perl... I have an array -

@a = (10,20,30,40);

Since '$' gives the scalar of a array ,

No it doesn't. I'm not sure what you mean. Do you mean $a is the same
as scalar(@a) ? No, that's not true.

i expect "print $a" to give the no.
of elements in the array...

No, @a and $a are two completely separate variables.

I have to confess this is rather messy in Perl5 - apparently it'll all
be different in Perl6.

In Perl5 @a is the array called 'a' and $a is a separate scalar variable
also called 'a'. Confusingly $a[0] is the first element of @a and has
nothing to do with $a. $#a is the last subscript of @a.

This is all explained in some detail in the perldata manual.

 

[vnick]

$x=@a is the evaluation of an array (a list) in a scaler context which
gives by definition the number of array elements whereas this 'print
"$a"' prints the scalar var (no evaluation within " ") $a which has
nothing to do with @a.
On the contrary you can define $a and @a at the same time not affecting
each other.
To get the number of elements of an array use
$#a + 1 or
scalar(@a) or
print @a ."\n"; (but not: print "@a\n"; !!!)

Hope that helps.

 

[Raghavendra Mahuli]

Thanx for all the responses....

Subject: a simple question

Please put the subect of your post in the Subject of your post.

Hi all,
I have a simple question in perl... I have an array -

@a = (10,20,30,40);

Since '$' gives the scalar of a array ,

No it doesn't. I'm not sure what you mean. Do you mean $a is the same
as scalar(@a) ? No, that's not true.

i expect "print $a" to give the no.
of elements in the array...

No, @a and $a are two completely separate variables.

I have to confess this is rather messy in Perl5 - apparently it'll all
be different in Perl6.

In Perl5 @a is the array called 'a' and $a is a separate scalar variable
also called 'a'. Confusingly $a[0] is the first element of @a and has
nothing to do with $a. $#a is the last subscript of @a.

This is all explained in some detail in the perldata manual.

 

[George]

Hi all,
I have a simple question in perl... I have an array -

@a = (10,20,30,40);

Since '$' gives the scalar of a array , i expect "print $a" to give
the no. of elements in the array...
But it dosent work.. However if i copy it to a scalar and then print
it, it works.. Can u pls explain why it is so?
Here is the program listing:

@a = (10,20,30,40);
$x= @a;
print $a;
print $x;

thanx in advance,
regards,
raghu

In perl your best friend is

use strict;
use warnings;