Is this the correct way to build a Perl hash that utilizes arrays?
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Published on 2010-03-24T05:24:17Z
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2010/03/24
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This is the first time I have manipulated hashes and arrays in this way -- and it is working. Basically, for every key there are multiple values that I want to record and then print out in the form "key --> value --> value --> val..."
My code is as follows. I am surprised that it works, so concerned that it works "by mistake". Is this the correct way to accomplish this task, or is there a more efficient or appropriate method?
while ($source =~ m/(regex)/g) { #Get all key names from source
$listkey = $1; #Set current list key to the current regex result.
$list{$listkey} = ++$i unless $list{$listkey}; #Add the key to the hash unless it already exists.
$list{$listkey} = [] unless exists $list{$listkey}; #Add an array for the hash unless the hash already exists.
while ($loopcount==0) {
if ($ifcount==0) {
$listvalue=result_of_some_function_using_list_key; #Get the first list value from the list key.
$ifcount++; #Increment so we only get the first list value once.
} else {
$listvalue=result_of_some_function_using_list_value; #Update the last list value.
}
if ($listvalue) { #If the function returned a value...
push @{$list{$listkey}}, $listvalue; #...then add the value to the hash array for the key.
} else { #There are no more values and we need a new key.
$listkey=0; #Reset variable.
$domain=0; #Reset variable.
$loopcount++; #Increment loop counter to exit loop.
}
}
$ifcount=0; #Reset count variable so the next listvalue can be generated from the new key.
$loopcount=0; #Reset count variable so another loop can begin for a new key.
}
foreach $listkey (keys %list) { #For each key in the hash.
print "$listkey --> "; #Print the key.
@values = @{$list{$listkey}}; #Reference the arrays of the hash.
print join ' --> ', @values; #Print the values.
print "\n"; #Print new line.
}
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