comment on

I would have used '-1' as the subscript. Would have. As of about 5 minutes ago I changed my mind as to the appropriateness of using -1 as a subscript.

Consider the following blocks...

$[ = -4;
@a = (qw(a b c d e f g h i j));
print $a[-1], "\n";
print $a[$#a], "\n";
__DATA__
d
j
[download]

and

$[ = 0;
@a = (qw(a b c d e f g h i j));
print $a[-1], "\n";
print $a[$#a], "\n";
__DATA__
j
j
[download]

There is some DWIMmery with the -1 option that could cause problems, especially if you are working on old, or someone else's code of unknown usage or localization of the $[ variable. And yes, I have read the disclaimers not to use the $[ variable in the fine manual. I didn't say that I would use the variable. :-)

Update: This is perl, v5.8.8 built for PA-RISC2.0

Comparison

Update #2: Comparison of perl binary available on this machine:

for x in 100 1 0 -1 -6 -7 -11 -12 -99; do
    perl -le "\$[=$x; my @ra=qw(a b c d e f); print \$[, ': -1:' , \$r
+a[-1], ': $#: ', \$ra[\$#ra]"
done
[download]

This is perl, version 5.005_02 built for PA-RISC1.1

100: -1: f: $#: f
1: -1: f: $#: f
0: -1: f: $#: f
-1: -1: f: $#: f
-6: -1: f: $#: f
-7: -1: f: $#: e
-11: -1: f: $#: a
-12: -1: f: $#: 
-99: -1: f: $#:
[download]

This is perl, v5.8.8 built for PA-RISC2.0

100: -1: f: $#: f
1: -1: f: $#: f
0: -1: f: $#: f
-1: -1: a: $#: f
-6: -1: f: $#: f
-7: -1: : $#: e
-11: -1: : $#: a
-12: -1: : $#: 
-99: -1: : $#:
[download]

Conclusion: Don't use $[ as anything other than 0 (as presented by a couple of other monks so far.

--MidLifeXis

The tomes, scrolls etc are dusty because they reside in a dusty old house, not because they're unused. --hangon in this post

In reply to Re^2: A Better Way to Find the Position of the Last Non-Whitespace Character in the Last Element of an Array. by MidLifeXis
in thread A Better Way to Find the Position of the Last Non-Whitespace Character in the Last Element of an Array. by NateTut

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		`&`
	<		`<`
	>		`>`
	[		`[`
	]		`]`

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.