hash problem

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

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Re: hash problem by robartes (Priest) on Jun 08, 2005 at 08:56 UTC
I don't know whether this is part of a larger script, but `$refnum` never gets set in this snippet, so you are storing your data in a hash entry with an empty key. That's why the entry with key '1' is ~~undefinded~~ undefined, triggering your die. Perhaps in the while loop you meant: `$names{$ref}=$str;` Update: stop inventing new verbs CU Robartes-	[reply] [d/l] [select]
Re: hash problem by muntfish (Chaplain) on Jun 08, 2005 at 08:53 UTC
It's not necessarily true that it is "unable to perform the last line of code". The code after the `or` will be run if the results of the previous code was 0, empty string, or undefined. So if `$names{1}` is any of those things, your `die` will be called. Is that `die` in the right place anyway? Looks like it should be after your `open`: `open (name, "<data/gly.txt") or die "unable to open";` [download] It's more common to use CAPS for file handles, by the way. Hope this helps - if not please post a specific example of your input to illustrate what's going on. s^^unp(;75N=&9I<V@`ack(u,^;s\|$.+\`\|"$`$'\"$&\"$"\|ee;/m.+h/&&print$&	[reply] [d/l] [select]
Re^2: hash problem by Anonymous Monk on Jun 08, 2005 at 08:57 UTC
if i print $structure i get nothing at all. the file split looks like: `1\| h20 2\| acyl etc` [download] so the $structure when $number =1 should be h20	[reply] [d/l]
Re: hash problem by holli (Abbot) on Jun 08, 2005 at 08:56 UTC
err, you split into $ref and then use $refnum? Apparently those 2 are not the same variables. How do you make sure $number equals $ref/$refnum? I bet this is one of the cases where `use strict;` would help. holli, /regexed monk/	[reply] [d/l]
Re^2: hash problem by Anonymous Monk on Jun 08, 2005 at 08:59 UTC
sorry yes ur right posted wrong code $refnum should be $ref	[reply]
Re: hash problem by davidj (Priest) on Jun 08, 2005 at 09:02 UTC
First, I think you might have an error in the code you submitted. I assume that `$names{$refnum} = $str;` [download] should be `$names{$ref} = $str;` [download] Second, the reason the code is dying is because on the last line, `$names{$number}` does not exist. It might be a good idea to take a look at what `$names` is actually holding after the loop. A good way to see that is to use `Data::Dumper` `#!/usr/bin/perl use Data::Dumper; %names; { open(name, "<data/gly.txt"); while(<name>) { ($ref, $str) = split /\\|/; $names{$ref} = $str; } } print Dumper(%names);` [download] This will help you track down the problem. davidj	[reply] [d/l] [select]
Re^2: hash problem by Anonymous Monk on Jun 08, 2005 at 09:08 UTC
it would appear that the number of lines in the hash is double of that in the gly file. $var1 = undef $war2 = 'h20' etc	[reply]
Re^3: hash problem by davidj (Priest) on Jun 08, 2005 at 09:11 UTC
The hash has not doubled. Rather, `$var1 = undef` is the key to the first hash element, `$var2 = 'h20'` is the value of the first hash element, etc. The good news is, this verifies the problem. That is, your keys are empty. Please show us the content of the text file you are using. That will certainly help us help you resolve the problem. davidj	[reply] [d/l] [select]
Re^4: hash problem by Anonymous Monk on Jun 08, 2005 at 09:14 UTC
Re: hash problem by Fletch (Bishop) on Jun 08, 2005 at 12:26 UTC
And no one else has explicitly mentioned it, but just having the name of a hash in void context (`%names;` in your code) doesn't do anything (or at least anything useful). You probably meant `my %names;`, but then you're not using strict or warnings so you wouldn't have gotten any gripes. -- We're looking for people in ATL	[reply] [d/l] [select]
Re: hash problem by murugu (Curate) on Jun 08, 2005 at 09:54 UTC
Hi, The code you written have some typo errors. You have assigned splitted values into $ref and $str, but you are storing the $str to an hash %names with key as $refnum which in turn is undefined. That is why die part is getting executed. Regards, Murugesan Kandasamy.	[reply]