Re: Iterating over Arrays

[William Torrez Corea]

On Sun, Sep 25, 2022 at 12:02 PM Mike  wrote:

>
> Your version produces this output in Perl 5.30.0:
>
> this
> that
> Use of uninitialized value $element in concatenation (.) or string at
> trash.pl line 14.
>
> Use of uninitialized value $element in concatenation (.) or string at
> trash.pl line 14.
>
> Use of uninitialized value $element in concatenation (.) or string at
> trash.pl line 14.
>
> bad idea
>
> Which is what I would expect.
>
>
>
> Another version:
>
> use strict;
> use warnings;
>
> my @words = ("this","that");
>
> $words[5] = "bad idea";
>
> for my $element (@words){
>  if (defined $element) {
>  print "$element\n";
>  }
>  else {
>  print "undefined\n";
>  }
> }
>
> print "\a";
>
>
> __END__
>
>
>
> Output:
>
> this
> that
> undefined
> undefined
> undefined
> bad idea
>
>
> Mike
>
>
> On 9/24/22 20:00, William Torrez Corea wrote:
> > What happen with my code?
> >
> > use strict;
> > use warnings;
> > use diagnostics;
> >
> > my @words = ("this","that");
> >
> > # With this code
> > $words[5] = "bad idea";
> >
> > for my $element (@words){
> >  print "$element\n";
> > }
> >
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > ~
> > "words.pl" 13L, 167B   1,1   All
> >
> >
> > Use of uninitialized value $element in concatenation (.) or string at
> > words.pl line 11.
> >   at words.pl line 11.
> >
>
>

I have the following version:

v5.32.1

-- 

With kindest regards, William.

⢀⣴⠾⠻⢶⣦⠀
⣾⠁⢠⠒⠀⣿⡁ Debian - The universal operating system
⢿⡄⠘⠷⠚⠋⠀ https://www.debian.org
⠈⠳⣄

Re: Iterating over Arrays

[Mike]

Your version produces this output in Perl 5.30.0:

this
that
Use of uninitialized value $element in concatenation (.) or string at 
trash.pl line 14.


Use of uninitialized value $element in concatenation (.) or string at 
trash.pl line 14.


Use of uninitialized value $element in concatenation (.) or string at 
trash.pl line 14.


bad idea

Which is what I would expect.



Another version:

use strict;
use warnings;

my @words = ("this","that");

$words[5] = "bad idea";

for my $element (@words){
    if (defined $element) {
    print "$element\n";
    }
    else {
    print "undefined\n";
    }
}

print "\a";


__END__



Output:

this
that
undefined
undefined
undefined
bad idea


Mike


On 9/24/22 20:00, William Torrez Corea wrote:

What happen with my code?

use strict;
use warnings;
use diagnostics;

my @words = ("this","that");

# With this code
$words[5] = "bad idea";

for my $element (@words){
 print "$element\n";
}

~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
"words.pl" 13L, 167B   1,1   All


Use of uninitialized value $element in concatenation (.) or string at
words.pl line 11.
  at words.pl line 11.

Re: Iterating over Arrays

[Ken Peng]

Hello

Try with this code:

use strict;
use warnings;
use Data::Dumper;

my @words = ("this","that");

# With this code
$words[5] = "bad idea";

print Dumper \@words;

And it outputs:

$VAR1 = [
  'this',
  'that',
  undef,
  undef,
  undef,
  'bad idea'
];


so $words[2], $words[3], $words[4] have been defined as undef automatically.

You'd better use a "push" method for a list operation like this.

Thanks


William Torrez Corea wrote:

What happen with my code?


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Iterating over Arrays

[William Torrez Corea]

What happen with my code?

use strict;
use warnings;
use diagnostics;

my @words = ("this","that");

# With this code
$words[5] = "bad idea";

for my $element (@words){
print "$element\n";
}

~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
"words.pl" 13L, 167B   1,1   All


Use of uninitialized value $element in concatenation (.) or string at
words.pl line 11.
 at words.pl line 11.

-- 

With kindest regards, William.

⢀⣴⠾⠻⢶⣦⠀
⣾⠁⢠⠒⠀⣿⡁ Debian - The universal operating system
⢿⡄⠘⠷⠚⠋⠀ https://www.debian.org
⠈⠳⣄

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