I recently posted a question asking for help in sorting an array of hashes by the values of multiple hash keys. I generally received answers relating to the sort function, which at first glance appeared to work. However, a closer look revealed that the nature of the sort function causes any new sort done on something previously sorted causes all order from the previous sort to be discarded. I came up with the following to get around this problem. I'd be very interested to hear comments, and suggestions for improvement.
sub sorthasharray($$) { # takes reference to array of hashes, and arra
+y of key names to sort by.
        my ($hasharray, $keylist) = @_;
        my $keyCount; # counter
        my $hashCount; # counter
        for $hashCount ( 0 .. $#$hasharray ) {  # walk through the arr
+ay
                for $keyCount ( 0 .. $#$keylist ) { # walk through the
+ keys
                        if ( $$hasharray[$hashCount]{$$keylist[$keyCou
+nt]} =~ /^\d*?\.??\d*?$/ ) {  # check to see if this should be a nume
+ric comparison
                                my $zeros = 12 - (length($$hasharray[$
+hashCount]{$$keylist[$keyCount]}));  # find out how many zeros we nee
+d 
#to pad to the right to make a string comparison equivalent to a numer
+ic comparison 
#(this isn't onehundred percent accurate, especially for float numbers
+.  Anyone want to take a crack at it?
                                for $zeroCount ( 1 .. $zeros ) {
                                        $$hasharray[$hashCount]{sortke
+y} .= "0";  # padd the zeros
                                }
                        }
                        $$hasharray[$hashCount]{sortkey} .= $$hasharra
+y[$hashCount]{$$keylist[$keyCount]};  # build sortkey by concatenatin
+g all sort keys in order
                }
        }
        @$hasharray = sort { $$a{sortkey} cmp $$b{sortkey} } @$hasharr
+ay;  # do the sort
        for $hashCount ( 0 .. @$hasharray ) {
                delete $$hasharray[$hashCount]{sortkey};  # delete the
+ unneeded key from all the hashes
        }
}

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In reply to Sort Array of Hashes by values of multiple hash keys. by raflach

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