the answer to an 'uninitialized value, now how do I implement it?

Bismark has asked for the wisdom of the Perl Monks concerning the following question:

In the snippet below I have the dreaded "uninitialized value" I see the cause. $searchresult is initialized with three values, then when I try to use it in the print statement I try to give it seven values, 3 - 7 are the uninitialized culprits. I eventually want to have more than seven fields, so how do I initialize them in the beginning?

my $searchresult = search( part     => $part,
               rev      => $rev,
               filename => './file.db'           );

print $searchresult
  ? "Located Part Number: @{$searchresult}[0 .. 7]\n"
[download]

Comment on the answer to an 'uninitialized value, now how do I implement it? Download Code

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Re: the answer to an 'uninitialized value, now how do I implement it? by pfaut (Priest) on Jan 18, 2003 at 02:28 UTC
`my $searchresult = search( ... ); if ($searchresult) { my $count = $#$searchresult; $count = 7 if $count > 7; print "Located Part Numer: @{$searchresult}[0..$count]\n"; }` [download] `--- print map { my ($m)=1<<hex($_)&11?' ':''; $m.=substr('AHJPacehklnorstu',hex($_),1) } split //,'2fde0abe76c36c914586c';` [download]	[reply] [d/l] [select]
Re: the answer to an 'uninitialized value, now how do I implement it? by runrig (Abbot) on Jan 18, 2003 at 02:37 UTC
While declaring the array in the function, or before returning the result from the function, you can initialize the values if you want to: `# Before doing stuff with array my @array = ('') x 8; # do stuff with array # or before returning from function for (@array) { $_ = '' unless defined } #or #for (@array[0..7]) { $_ = '' unless defined } return @array;` [download]	[reply] [d/l]
Re: the answer to an 'uninitialized value, now how do I implement it? by graff (Chancellor) on Jan 18, 2003 at 02:33 UTC
Try this: `my $resultsize = @$searchresult; print "Located Part Number: @$searchresult[0..$resultsize]\n" if ( $resultsize );` [download] (I was puzzled at what appeared to be an incomplete ternary operator in your code -- there was an expression, a question mark, another expression, then nothing else, when there should have been a colon and a third expression.)	[reply] [d/l]
Re: Re: the answer to an 'uninitialized value, now how do I implement it? by Bismark (Scribe) on Jan 18, 2003 at 02:44 UTC
There is a colon and third expression, I left it out here since it is not involved with the error. I tried your suggestion and still get the uninitialized value error. After the error message it does print all the fields. So it is closer than I have gotten so far.	[reply]
Re: the answer to an 'uninitialized value, now how do I implement it? by Coruscate (Sexton) on Jan 18, 2003 at 04:46 UTC
psst... just for the record, you are printing out an array slice of 8 items, not 7. :) Always remember that arrays begin with the number 0. So when you say `@{$var}[0 .. 7]`, you are retrieving data from the array "slots" 0, 1, 2, 3, 4, 5, 6 and 7, making a total of 8 items. You know... just for the record :)	[reply] [d/l]