Re: Perl's feature to determine, in current point of loop, that this is the last one?

You could always watch for the last value in the list and test for that ..

my @values = qw/red green brown blue/;
foreach my $v ( @values ) {
  if ( $v eq $values[-1] ) {  #  Last value
  } else {                    #  All other values
  }
}
[download]

As you've already heard, there's nothing built in to Perl that handles that.

Alex / talexb / Toronto

Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.

Comment on Re: Perl's feature to determine, in current point of loop, that this is the last one? Download Code

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Re^2: Perl's feature to determine, in current point of loop, that this is the last one? by LanX (Saint) on Jan 24, 2022 at 02:19 UTC
> You could always watch for the last value in the list and test for that .. this only works if the last value is unique Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply]
Re^3: Perl's feature to determine, in current point of loop, that this is the last one? by talexb (Chancellor) on Jan 24, 2022 at 02:58 UTC
Absolutely right -- I knew that my approach had flaws, but the initial question was so vague I figured I'd throw my solution into the mix. The OP never explained why this feature was necessary .. it sounds more like a feature looking for a use case to me. Alex / talexb / Toronto Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.	[reply]
Re^4: Perl's feature to determine, in current point of loop, that this is the last one? by Fletch (Bishop) on Jan 25, 2022 at 17:05 UTC
WRT use case: one of the (admittedly few) places I've seen something like this (which is why I mentioned the iterator module from TT) is in templating where you want to "decorate" the first or last item in a list differently than other items. Think maybe pagination where displaying a chunk from the middle and you want those items to have a link to the next or subsequent sets of results (terrible handwavy sample follows, and yes you could do similar stuff with JS or CSS instead). `<table> [% FOREACH item IN current_chunk %] <tr> [% IF loop.first %]<td> << </td>[% ELSE %]<td> </td>[% END +%] <td>[% item %]</td> [% IF loop.last%]<td> >> </td>[% ELSE %]<td> </td>[% END %] </tr> [% END %] </table>` [download] Edit: And I realized I hadn't linked to the TT FOREACH docs which explain the `loop` magic (which is Template::Iterator under the hood). The cake is a lie. The cake is a lie. The cake is a lie.	[reply] [d/l] [select]
Re^5: Perl's feature to determine, in current point of loop, that this is the last one? by talexb (Chancellor) on Jan 25, 2022 at 21:24 UTC
Re^6: Perl's feature to determine, in current point of loop, that this is the last one? by afoken (Chancellor) on Jan 26, 2022 at 15:49 UTC
Re^4: Perl's feature to determine, in current point of loop, that this is the last one? by ikegami (Patriarch) on Jan 24, 2022 at 04:01 UTC
It's so easy to avoid the limitation. Replace `$v eq $values[-1]` with `\$v == \$values[-1]`	[reply] [d/l] [select]
Re^5: Perl's feature to determine, in current point of loop, that this is the last one? by LanX (Saint) on Jan 24, 2022 at 08:44 UTC
Re^6: Perl's feature to determine, in current point of loop, that this is the last one? by ikegami (Patriarch) on Jan 25, 2022 at 14:46 UTC


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