This is something that I like to use a closure for. The following will print a table with all of the URL and HTML codes, along with the symbol each stands for and the extended ASCII value. The $toggle variable controls the background color used for each row of the table.

use CGI;
use HTML::Entities;
use URI::Escape;
my $q = CGI->new;

my $data;
my $toggle    = initToggle( 1 );

for my $ASCII ( 0 .. 255 ) {

    # The following is a hexadecimal list of characters that must be e
+ncoded
    # in query strings
    my $cgi_chars  = '\x00-\x29\x2b\x2c\x2f\x3a-\x40\x5b-\x5e\x60\x7b-
+\xff';

    # The following is a hexadecimal list of characters that often hav
+e their
    # HTML character code equivalent used instead of the characters th
+emselves
    my $html_chars = '\x00-\x2f\x3a-\x40\x5b-\x5e\x60\x7b-\xff';

    my $char      = chr( $ASCII );                         # The actua
+l character
    my $symbol    = encode_entities( $char, $html_chars ); # HTML code
+ for Web page
    my $escaped   = uri_escape( $char, $cgi_chars );       # CGI repre
+sentation
    my $html_code = encode_entities( $symbol );            # Re-encode
+ HTML code so that it
                                                                # disp
+lays properly
    if ( $escaped eq '%20' ) { $escaped .= ' or +' };      # a space m
+ay be %20 or a +
    my @bgcolor   = ( '#FFFFFF', '#CCCCCC' );
    $data .= $q->Tr( { -align   => 'right',
                       -bgcolor => $bgcolor[ &$toggle ] },
                     $q->td( 
                             [ $ASCII < 33 ? '&nbsp;' : $symbol, $ASCI
+I, $escaped, $html_code ] 
                           ) 
                   );
}

print $q->header,
      $q->start_html,
      $q->table( $data ),
      $q->end_html;

sub initToggle {
    my $limit = shift;
    my $count = 0;
    my $bit   = 0;
    unless ( $limit > 0 ) { die "initToggle() requires a positive argu
+ment\n" };
    return sub {
        $bit ^= 1 if $count++ % $limit == 0;
    }
}

[download]

In fact, if you wanted to, you could easily update the closure to return the color values themselves instead of the array index.

Yeah, I'm sure some of you recognize that table :)

Cheers,
Ovid

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In reply to (Ovid) Re: alternating row colors by Ovid
in thread alternating row colors by qball

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