in reply to 'my' headache...why doesn't this work?

For those wondering if I am losing the variable outside its 'my' scope: I am printing the result immediately after the calculations, like:

my $columnsum += $_->[$colnum] for @data;
print "Total value = $columnsum";

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...and...

$columnsum = 0;
$columnsum += $_->[$colnum] for @data;
print "Total value = $columnsum";

[download]

======================
Sean Shrum
http://www.shrum.net

Replies are listed 'Best First'.
Re: Re: 'my' headache...why doesn't this work?
by tachyon (Chancellor) on Apr 05, 2002 at 10:20 UTC 
    # your code
my $columnsum += $_->[$colnum] for @data;

# is effectively the same as
for (@data) {
   my $columnsum += $_->[$colnum]
}

# so as expected $columnsum is effectively localised to that block (li
+ne).

my $i += $_ for 1..3;
print "localised (1) \$i='$i'\n";
for (1..3) { my $i += $_ }
print "localised (2) \$i='$i'\n";
$i += $_ for 1..3;
print "not localised (1) \$i='$i'\n";
for (1..3) { $i += $_ }
print "not localised (2) \$i='$i'\n";
print "Oops, forgot to zero a widely scoped var!";

    [download]

    cheers

    tachyon

    s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

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