What stops you ...

Nothing stops the beginner from using the first approach or from pitching headlong into the yawning chasm it opens up, for the  foreach loop is mutating the  @data "source" array. Of course, map also aliases  $_ to the items of the list over which it iterates and so presents the same pitfall, but I agree it is the idiomatic and preferable approach — but let beginners beware! 

c:\@Work\Perl>perl -wMstrict -MData::Dump -le
"my @data = 1 .. 4;
 dd \@data;
 ;;
 my @results;
 foreach (@data) {
   $_ = $_ * 13;
   push @results, $_;
   }
 ;;
 dd \@data;
 dd \@results;
"
[1 .. 4]

[13, 26, 39, 52]

[13, 26, 39, 52]

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In reply to Re^2: Getting a result from "foreach" block by AnomalousMonk
in thread Getting a result from "foreach" block by v_melnik

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