use strict;
use warnings; 

my @array = (1,1,1,2,2,2,2,2,3,3,3,4,4,4,4,4,4,5,5,6);

# tricky and destructive
1 until 4 == pop @array;
print "last occurence of 4 was at ",$#array + 1," position\n";

# or even uglier
@array = (1,1,1,2,2,2,2,2,3,3,3,4,4,4,4,4,4,5,5,6);
1 until 4 == pop @array;
push @array, 4;
print "last occurence of 4 was at $#array position\n";

# non destructive copying $#array
@array = (1,1,1,2,2,2,2,2,3,3,3,4,4,4,4,4,4,5,5,6);
my $lastindex = $#array;
$lastindex-- until $array[ $lastindex ] == 4;
print "last occurence of 4 is at $lastindex position\n";

# non destructive taking last of sort-grepping on indexes
print "last occurence of 4 is at ",( sort{ $a <=> $b }grep{ $array[$_]
+ == 4 }0..$#array )[-1]," position\n";
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