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3 field hash, value lookup by key is 2nd field

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April 28, 2002 11:20
3 field hash, value lookup by key is 2nd field
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Goal- look up value in a hash of 3 fields where middle is key field for
lookup. The build hash from text file part below is working fine.
Then I read in a transaction file with field $sicode which should
lookup/chain/match to the key ($sig)in the hash and find a weight (3rd field
in hash, $wgt), and a code, $type(1st field).
I can't get the basic lookup on key $sig to work.

I have created the hash from a text file thusly

while (<INFILE>) {
   ($type,$sig, $wgt) = split ','; # splits $_ by default
   chomp $wgt;
   print "2 $type   $sig   $wgt \n";# single-spaced output
   $sigwgthash{$sig}{'type'} = $type;
   $sigwgthash{$sig}{'wgt'} = $wgt;
then verified its' existance in memory and can print each field by doing

 foreach $key (sort keys %sigwgthash) {
   print "$key has a wgt of $sigwgthash{$key}{'wgt'} \n";
Now  why is it so hard to find a basic "lookup value by key" using key field
from another file??  But remember, the key I need to use is the MIDDLE of
the 3 fields in the hash.

When trying a distinct lookup within a "foreach" read of the non-hash
transaction file, .  I tried..
print "wgthash $wgthash     sigwgt $sigwgthash{$sicode}{'wgt'}     \n";

where $sicode is the field from the other file to be matched in the hash
keys.  The other words in front are just to describe field in that debug
print line.
I get blanks/nothing... no match evidently.

Most tutorials, Perl Monks, etc do not seem to cover many basics one notch
above the most basic. I personally found the Programming Perl/Oreilly book
to be NOT very helpful.
Sure would appreciate any help.

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