Re: Use of uninitialized value within

I am unable to duplicate your problem with my perl v5.16.3. I can suggest several improvements to your code.

Always use strict and warnings.

Use of printf with only a format is confusing. Use print

Your math is unnecessarily complicated.

use strict;
use warnings;
use POSIX qw(floor);
my @PC1=(58,50,42,34,26,18,10,2,
      60,52,44,36,28,20,12,4,
      62,54,46,38,30,22,14,6,
      64,56,48,40,32,24,16,8,
      57,49,41,33,25,17,9,1,
      59,51,43,35,27,19,11,3,
      61,53,45,37,29,21,13,5,
      63,55,47,39,31,23,15,7);

my @parr=('0','M','0','A','0','I','0','L');
print $parr[floor( $PC1[$_]/8 )], "\n" for (0..63);
[download]

My use of 'floor' is not strictly necessary in this case, but is recommended for the reason explained in int.

Comment on Re: Use of uninitialized value within Download Code

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Re^2: Use of uninitialized value within by AnomalousMonk (Archbishop) on Feb 03, 2015 at 17:51 UTC
I am unable to duplicate your problem with my perl v5.16.3. I can duplicate the problem with both Strawberry 5.14.4.1 and ActiveState 5.8.9, both under Win32. c:\@Work\Perl>perl -wMstrict -le "use POSIX qw(floor); ;; print 'perl version ', $]; ;; my @PC1=(58,50,42,34,26,18,10,2, 60,52,44,36,28,20,12,4, 62,54,46,38,30,22,14,6, 64,56,48,40,32,24,16,8, 57,49,41,33,25,17, 9,1, 59,51,43,35,27,19,11,3, 61,53,45,37,29,21,13,5, 63,55,47,39,31,23,15,7); ;; my @parr=('0','M','0','A','0','I','0','L'); printf $parr[floor( $PC1[$_]/8 )] for (0..63); " perl version 5.014004 Use of uninitialized value in printf at -e line 1. L0I0A0M0L0I0A0M0L0I0A0M0L0I0A0ML0I0A0M0L0I0A0M0L0I0A0M0L0I0A0M0 [download] As in the OPed code, the problem arises from the element of 64 in the `@PC1` array producing an index of 8 into the `@parr` array, the highest valid index of which is 7. Give a man a fish: `<%-(-(-(-<`	[reply] [d/l] [select]
Re^2: Use of uninitialized value within by AnomalousMonk (Archbishop) on Feb 04, 2015 at 00:52 UTC
Your math is unnecessarily complicated. One could further simplify the math by taking advantage of the fact that the `[ ]` subscript operator does its own 'floor' operation by just throwing away the fractional part of the (inherently) double number: c:\@Work\Perl>perl -wMstrict -le "use POSIX qw(floor); ;; print 'perl version ', $]; ;; my @PC1=(58,50,42,34,26,18,10,2, 60,52,44,36,28,20,12,4, 62,54,46,38,30,22,14,6, 64,56,48,40,32,24,16,8, 57,49,41,33,25,17, 9,1, 59,51,43,35,27,19,11,3, 61,53,45,37,29,21,13,5, 63,55,47,39,31,23,15,7); ;; my @parr = qw(0 M 0 A 0 I 0 L); printf $parr[floor( $PC1[$_]/8 )] for (0..63); print ''; printf $parr[ $_ / 8 ] for @PC1; " perl version 5.014004 Use of uninitialized value in printf at -e line 1. L0I0A0M0L0I0A0M0L0I0A0M0L0I0A0ML0I0A0M0L0I0A0M0L0I0A0M0L0I0A0M0 Use of uninitialized value in printf at -e line 1. L0I0A0M0L0I0A0M0L0I0A0M0L0I0A0ML0I0A0M0L0I0A0M0L0I0A0M0L0I0A0M0 [download] (Of course, this doesn't address the root problem of generating an index that's out of range!) Give a man a fish: `<%-(-(-(-<`	[reply] [d/l] [select]
Re^2: Use of uninitialized value within by GrandFather (Saint) on Feb 03, 2015 at 19:47 UTC
You don't see the warning because you didn't run the script with warnings turned on. Most likely the OP used -w on the command line to achieve that. Running the updated version of the script that you provided does show the warning. I guess you posted the code without running it? Perl is the programming world's equivalent of English	[reply]
Re^2: Use of uninitialized value within by BillKSmith (Monsignor) on Feb 03, 2015 at 23:06 UTC
Sorry guys, I missed the message when it scrolled off the screen. Bill	[reply]