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Re: comparing and removing values from an array of hashes

by roboticus (Chancellor)
on Oct 22, 2012 at 14:15 UTC ( #1000349=note: print w/ replies, xml ) Need Help??

in reply to comparing and removing values from an array of hashes


I'd suggest adding another column to your data, and taking two passes through the data:

On the first pass, you can add the new column. Add 0 if there's no value in check, 1 otherwise. Also in this pass, keep track of the maximum quantity and maximum price.

On the second pass, you can use your maxima that you found in pass 1 and selectively turn the new column to 0 if you want to discard the row.

Finally, take a pass through the data and copy the rows that still have a 1 in the new column to your results array.

Strictly, you don't need to add another column for your task, as you could easily perform the missing value test on pass 2. I thought I'd suggest adding it in case you come up with new criteria that may require yet another pass over the data. It's just a simple sifting technique where you keep marking rows to discard. Once you're done, whatever has a 1 in the new column passed all your tests.


When your only tool is a hammer, all problems look like your thumb.

Comment on Re: comparing and removing values from an array of hashes
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Re^2: comparing and removing values from an array of hashes
by perl_walker (Novice) on Oct 22, 2012 at 14:26 UTC

    Hi rizzler,

    I think this may help you,

    my %quantity=(YEAR => 5, MONTH => 4, WEEK => 3, DAY => 2, HOUR =>1); my $a1="A,Star_1GB,MONTH,1000,0"; my $b1="B,Unlim60,MONTH,1000,6000"; my $b2="B,Unlim60,YEAR,1000,6000"; my $c1="C,Unlim,DAY,50,6000"; my $c2="C,Unlim,HOUR,50,6000"; my $d1="D,,MONTH,500,8000"; my @vals = ($a1, $b1, $b2, $c1, $c2, $d1); @vals = map{$_->[0]} sort{$quantity{$b->[1]} <=> $quantity{$a->[1]}} s +ort{$b->[2] <=> $a->[2]} sort{$b->[3] <=> $a->[3]} map{[$_, /(YEAR|MO +NTH|WEEK|DAY|HOUR),([^,]*),([^,]*)$/i]} @vals; print join("\n",@vals);

    Output will be:

    B,Unlim60,YEAR,1000,6000 B,Unlim60,MONTH,1000,6000 A,Star_1GB,MONTH,1000,0 D,,MONTH,500,8000 C,Unlim,DAY,50,6000 C,Unlim,HOUR,50,6000

      Thanks :) this does almost everthing I needed. Even with my poor skills I can probably work out the rest.



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