in reply to Re^2: Special formatting of error messages
in thread Special formatting of error messages

Let me break this down: 

my $maxsize = 0;
map {chomp; $maxsize = ($maxsize>length)?($maxsize):(length)} @lines;

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If I were to write this using the 'Software Engineer' side of my brain, it would look like: 

my $maxsize = 0;
foreach my $line (@lines)
{
  chomp $line;   #remove \n from the line
  my $lineLength = length($line);  #Determine length of line

  #if line is longer than the longest 
  #line I've seen so far then make it $maxsize.
  if($lineLength>$maxsize)  
  {
    $maxsize = $lineLength;
  }
}

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code hasn't been tested

It sounds like the part that is throwing you is the '?:' conditional operator: 

  $result = ($x > $y)?(14):(-5)

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It's a one line conditional. It's documented in perldoc perlop (look for 'Conditional Operator'). The condition is evaluated and if true, the first value is assigned into $result (14) if it's false, the second value is assigned into $result (-5).

I hadn't done it this way before and I thought your question was a good opportunity to try it out. I've seen it before in code, just haven't had a chance to see if it suits me.

To any monks that have read this far. What's the minimal code for finding the lonest line in an array?

"Look, Shiny Things!" is not a better business strategy than compatibility and reuse.

Replies are listed 'Best First'.
Re^4: Special formatting of error messages
by Ronnie (Scribe) on Feb 02, 2005 at 15:29 UTC
    Thanks for the explanation, you correctly identified the area I was having problems with and have explained it fully.
    Cheers,
    Ronnie
    PS I just need to find out how to centre the text now.
[reply]

      Bah! Looks like printf won't do centering. Have to calculate the space by hand. (As another responder posted...) 

      use strict;
 
my @lines = <DATA>;
my $maxsize = 0;
map {chomp; $maxsize = ($maxsize>length)?($maxsize):(length)} @lines;
print "max size: $maxsize\n";
my $windowSize = $maxsize +4;
my $bar = '*' x $windowSize . "\n";
 
foreach (@lines)
{
  # calculate space between this line and window border
  my $space = $maxsize - length($_);
 
  # determine if the space is an odd or even number
  my $odd = $space%2;
 
  # half the space will go on the left, half will
  # go on the left (plus one if it was odd).
  my $spacer = int($space/2);
 
  print($bar);
  print('* ' . ' ' x $spacer . $_ . ' ' x ($spacer + $odd) . " *\n");
  print($bar);
}
 
 
__DATA__
some lines
that are of different sizes
Some small
really small.
----------------some large---------------------
--------------------------------------------------some huge-----------
+---------------------------------------
...

      [download]
      "Look, Shiny Things!" is not a better business strategy than compatibility and reuse.

[reply]
[d/l]
Re^4: Special formatting of error messages
by eric256 (Parson) on Feb 02, 2005 at 17:02 UTC

    The shortest I've got so far is my $max = (sort map { length } @test)[0]; This can also get the shortest by using -1 instead of 0.


    ___________
    Eric Hodges
[reply]
[d/l]

      Bravo! I hadn't thought about doing it with sort.

      I came up with: 

      use List::Util qw|max|;
...
my $maxsize = max(map {chomp; length} @lines);

      [download]
      "Look, Shiny Things!" is not a better business strategy than compatibility and reuse.

[reply]
[d/l]

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