About personal function

[dideod.yang]

Hi monks. I want to achieve using personal function with many arrays. Below script, I show you sample. According script, only print A... I want to print all of values(A B C) in @x. How can I achieve my personal function.

my (@x,@y);
@x =( "A" "B" "C");
@y =( "C" "D" "F");

&test(@x,@y):

sub &test{
 @test = @_[0];
 print "@test\n";
}

[kevbot]

Hello dideod.yang,

Your script is not valid perl syntax. I recommend that you take a closer look at some documentation in order to become more familiar with perl syntax and debugging.

• Getting Started with Perl
• Basic debugging checklist

Here is a modified version of your script that will print the first element of @x, which is 'A'. It will also print all the elements of @x (joined by commas).

#!/usr/bin/env perl

use strict;
use warnings;

my @x = ( 'A', 'B', 'C');
my @y = ( 'C', 'D', 'F');

test(\@x,\@y);

sub test{
    my ($x, $y) = @_;
    print "First element of x is: ", $x->[0], "\n";
    print "All elements of x are: ", join(', ', @{$x}), "\n";
}

[NetWallah]

Also see Pass-by-Reference to understand why kevbot passed reference to arrays.

[atcroft]

(First of all, the code you gave throws the error message "Illegal declaration of anonymous subroutine", which would be fixed by removing the & from the sub declaration. Also, if "@test" is changed to "my @test" in line 8, the code will work under "use strict" and "use warnings", both of which may be helpful to you later on.)

When your &test routine is entered, @_ will contain the contents of both @x and @y, flattened into a single array (i.e., @_ contains ( "A", "B", "C", "C", "D", "F", ) ). You, however, are currently assigning to @temp the value of @_[0] (better written as $_[0]), which is the first entry of @_ (or "A"). There are two ways I can see going. The simplest is to change that line to something like @test = @_;, wherein you will get the string "A B C C D F".

If you want to get them as separate arrays, then you can pass them by reference, and then loop through the elements in @test in the loop (example derivation below; the -l switch appends an appropriate EOL for each print statement).

Read more... (6 kB)

Hope that helps.