in reply to Multiple / Mapping Search and Replace

You should change: 

            chomp $_;

            # Split the line by whitespace
            my @array = split (/\s+/, $_);

            # If the first column of a line is blank whitespace, shift
+ it out so the
            # first column corresponds to actual user viewable data, w
+hich is the way
            # a user will count the columns, ignoring leading whitespa
+ce.
            if ($array[0] eq "") {
                shift (@array)
            }

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To: 

            # Split the line by whitespace
            my @array = split;

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Because split with no arguments ignores leading whitespace so there is nothing to remove and it also removes all trailing whitespace so there is nothing for chomp to remove. 


            while (<@array>) {

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That is short for: 

            while (glob join $", @array) {

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and it is usually written as: 

            foreach (@array) {

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Replies are listed 'Best First'.
Re^2: Multiple / Mapping Search and Replace
by VinsWorldcom (Prior) on Mar 18, 2009 at 00:48 UTC

    Thanks for the tips. Incorporated and tested fine.

    Question: What is better coding practice and quicker?

            if (defined($opt_ignore)) {
            if (defined($opt_reverse)) {
                $map{lc($array[1])} = $array[0]
            } else {
                $map{lc($array[0])} = $array[1]
            }
        } else {
            if (defined($opt_reverse)) {
                $map{$array[1]} = $array[0]
            } else {
                $map{$array[0]} = $array[1]
            }
        }

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    or

    $map{ (defined($opt_ignore) ? lc( (defined($opt_reverse) ? $array[1] :
+ $array[0])) : (defined($opt_reverse) ? $array[1] : $array[0])) } = (
+defined($opt_reverse) ? $array[0] : $array[1])

    [download]
[reply]
[d/l]
[select]
      I would avoid both of those approaches. The first involves too much repetition of code, and the second is too obfuscated. How about like this: 
      my ( $src, $dst ) = ( $opt_reverse ) ? ( 0, 1 ) : ( 1, 0 );

if ( $opt_ignore ) {
    $map{lc($array[$dst])} = $array[$src];
} else {
    $map{$array[$dst]} = $array[$src];
}

      [download]
      (I hope I got the polarity right on what "reverse" means, but in any case, I think you can see the point.)

      (update: got rid of the "defined()" call -- the option values should just be true or false, and undefined is false)

      Another update: better solution: 

      my ( $src, $dst ) = ( $opt_reverse ) ? (0,1) : (1,0);
my $key = ( $opt_ignore ) ? lc($array[$dst]) : $array[$dst];

$map{$key} = $array[$src];

      [download]
[reply]
[d/l]
[select]

      The first one looks a lot more readable and maintainable.   As for speed, you would have to use something like Benchmark to determine which is fastest.

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