how do I pass arrays from mainscript into the subroutine

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Hi,=0ALooking at the script below, how do I pass 2 arrays from the main scr=
ipt into =0Athe subroutine? Thanks #### script ######=0A#!/usr/bin/per=
l=0Ause strict;=0Amy @whatever =3D qw(a b c d e);=0Amy @test =3D qw(1 2 3 4=
5 6 7);=0A{  sub testing {  =A0 my (@data1 , @data2)=A0 =3D @_;=0A=
   print "\@data1 =3D @data1\n";  =A0 print "\@data2 =3D @data2\n";=
 }=0A}=0A&testing (@whatever ,@test);
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Re: how do I pass arrays from mainscript into the subroutine

On 11-05-07 11:47 AM, eventual wrote:
> Hi,
> Looking at the script below, how do I pass 2 arrays from the main script into
> the subroutine? Thanks
>
> #### script ######
> #!/usr/bin/perl
> use strict;
> my @whatever = qw(a b c d e);
> my @test = qw(1 2 3 4 5 6 7);
> {
> sub testing {
> my (@data1 , @data2) = @_;
> print "\@data1 = @data1\n";
> print "\@data2 = @data2\n";
> }
> }
> &testing (@whatever ,@test);

You have to use references to the arrays:

#!/usr/bin/env perl

use strict;
use warnings;

my @whatever = qw(a b c d e);
my @test = qw(1 2 3 4 5 6 7);

sub testing {
my @data1 = @{ $_[0] };
my @data2 = @{ $_[1] };

print "\@data1 = @data1\n";
print "\@data2 = @data2\n";
}

testing( \@whatever, \@test );

__END__

Also, don't call a sub with the &. Does can do unexpected things.

See:
perldoc perlreftut
perldoc perlref


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Re: how do I pass arrays from mainscript into the subroutine

>>>>> "SHC" == Shawn H Corey writes:


SHC> #!/usr/bin/env perl

that is not a good trick to run perl. also it forks off an extra process
which slows things down.

SHC> use strict;
SHC> use warnings;

SHC> my @whatever = qw(a b c d e);
SHC> my @test = qw(1 2 3 4 5 6 7);

SHC> sub testing {
SHC> my @data1 = @{ $_[0] };
SHC> my @data2 = @{ $_[1] };

why do you need to copy the arrays over? keep them as refs and
dereference them as needed.

my( $data1, $data2 ) = @_ ;

SHC> print "\@data1 = @data1\n";
SHC> print "\@data2 = @data2\n";
SHC> }

print "data1 = @{$data1}\n";
print "data2 = @{$data2}\n";

SHC> See:
SHC> perldoc perlreftut
SHC> perldoc perlref

those should be mentioned more prominently and earlier. obviously the OP
doesn't know about refs so they need to learn the basics.

uri

--
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Re: how do I pass arrays from mainscript into the subroutine

>
> Also, don't call a sub with the &. =A0Does can do unexpected things.
>

Just for my understanding, what are the other issues with &sub apart
from skipping prototype definitions?

Thanks,
Sandip

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Re: how do I pass arrays from mainscript into the subroutine

On 5/9/11 Mon May 9, 2011 8:03 AM, "Sandip Bhattacharya"
scribbled:

>>=20
>> Also, don't call a sub with the &. =A0Does can do unexpected things.
>>=20
>=20
> Just for my understanding, what are the other issues with &sub apart
> from skipping prototype definitions?

Please read the descriptions in 'perldoc perlsub'. Search for "Subroutines
may be called recursively' and the section titled 'Prototypes'.
Specifically, the use of the &sub form means that prototype checking will
not be done and, if no arguments are included in the subroutine call, the @=
_
array will not be initialized and will be whatever value it had at the time
of the call.

While the use of subroutine prototypes is rare and the absence of checking
not often a problem, having an unexpected value in @_ could cause unintende=
d
results.



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