Personally, I wouldn't break out on a condition related to the value of $i itself in such a loop, but I often run across circumstances such that I want to use the loop variable to store the last condition that was valid, when looping through a list of valid or invalid conditions. For example, 

my $condNum = 0;
for $condNum ( 1 .. 10 ) {
    forceSituation( $conditions[condNum] );
    my $result = measureSituation();
    push @results, $result;
    last if $result->is_error();
    more_manipulation(); # possibly do more stuff for this condition, 
+but only if it's not an error
}
datalog( value => $condNum, llim => 9.9, hlim => 10.1, name => 'number
+ of situations tested' );
datalog( value => fn(@results), llim => -2.7182818, hlim => 3.1415926,
+ name => 'result of those situations' )

[download]
... That loop wouldn't work in perl. But it doesn't seem an abuse of the loop counter, to me, to use the loop counter as the indicator of how many situations were actually tested. The code above seems more natural to me than 
my $lastCondNum = 0;
for my $condNum ( 1 .. 10 ) {
    ...
    $lastCondNum=$condNum, last     if $result->is_error()
    ...
}
...

[download]
Why require a second variable just to store the last condition number it happened to be in, when the loop variable seems a natural storage device for that information?

(In these situations, I'm generally in a hardware-specific language, not Perl, so that one annoyance of Perl doesn't usually affect me. But there are a plethora in the hardware-specific language that I wish it did more like Perl does, so not a fair balance, in my opinion. :-( )

In reply to Re^2: loop surprise by pryrt
in thread loop surprise by morgon

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