Re: Special variable - set array base

Jim, you're right. I forgot to show another important piece of my program. Here's a better snippet:

#!/usr/sbin/perl -w

use strict;

$[ = 7;    # set array base to 1
$, = ' ';    # set output field separator
$\ = "\n";    # set output record separator
...
while (<FILE>) {
    chomp;    # strip record separator
    @in_data = split(/ +/, $_);

    $out_raw = sprintf(" %8.0f %8.0f", $in_data[1], $in_data[2]);
...
[download]

My program runs fine, I'm just curious about the $_ variable and whether or not it is still in use.

Update: I checked perlvar, but it says pretty much the same thing as Programming Perl. It did add that the use of $[ is discouraged.

Comment on Re: Special variable - set array base Select or Download Code

Replies are listed 'Best First'.
Re: Re: Special variable - set array base by Jim Morrison (Novice) on Jul 03, 2002 at 22:22 UTC
Beleive me or not, I got different results when set `$[` to 1, 7 and 0 running your piece of code. (slightly modified, but you did not provided exact code to execute. and I'll show you my logs if needed.) About usage of "$_" variable -- beware, your "while(<FILE>)" - this loop corrupts "$_", and "local $_;" statement somewhere before that loop will be a good idea, just to preserve its value. Sins of Perl Revisited will get you an idea what I mean. Here's an excelent explanation about power plant... well, read on, this certainly worth it! Jim	[reply] [d/l]

Replies are listed 'Best First'.

Re: Re: Special variable - set array base
by Jim Morrison (Novice) on Jul 03, 2002 at 22:22 UTC

$[

About usage of "$_" variable -- beware, your "while(<FILE>)" - this loop corrupts "$_", and "local $_;" statement somewhere before that loop will be a good idea, just to preserve its value.

Sins of Perl Revisited will get you an idea what I mean. Here's an excelent explanation about power plant... well, read on, this certainly worth it!

Jim

[reply]
[d/l]