map processes a list and returns a list, so your need to assign the list back to your @data array (or a new array).

  @data = map { #? data is skiped when plotted
   if($maxreject[$i]) {
  $_ = "?$_" if($_ > $maxclip);
   }
   if($minreject[$i]) {
  $_ = "?$_" if($_ < $minclip);
   }
   $i++;
   $_; ######### YOU ALSO NEED TO PASS THE VALUE THROUGH!!
  } @data;
[download]

That said, a for loop might be a better choice, but it should work.

Update: As I said that your loop could be done as a for, I thought I ought show what I mean. I don't fully understand your algorithm, but either of the following would be functionally equivalent to your inner loop and (I think) they are somwhat easier to understand. Your choice is yours of course.

# as a for loop
for (@data} {
    $_ = '?'.$_    if $maxreject[$i]   && $_ > $maxclip 
            or $minreject[$i++] && $_ < $minclip
};
# or as a map, but different.
@data = map{ 
       $maxreject[$i]   && $_ > $maxclip 
    or $minreject[$i++] && $_ < $minclip
    ? '?'.$_
    : $_
} @data;
[download]

map processes a list and returns a list, so you need to assign the list back to your @data array (or a new array).

  @data = map { #? data is skiped when plotted
   if($maxreject[$i]) {
  $_ = "?$_" if($_ > $maxclip);
   }
   if($minreject[$i]) {
  $_ = "?$_" if($_ < $minclip);
   }
   $i++;
  } @data;
[download]

That said, a for loop might be a better choice, but it should work.

Thanks for the quick response! However, assigning @array = map {} @data produces the following in my data:

07/01 09:09:57 0 1 2 3 4 5
07/01 09:14:56 0 1 2 3 4 5
07/01 09:19:58 0 1 2 3 4 5
07/01 09:24:58 0 1 2 3 4 5
07/01 09:29:58 0 1 2 3 4 5
07/01 09:34:58 0 1 2 3 4 5
[download]

Hmm.

Sorry! Take another look, I've updated the previous answer.

With map, the value that gets passed out it the last value in the code block. In your case it was the $i++ expression, hence the counts you got. Add the new last line I indicate above and it should fix that. I didn't notice that the first time.

I still think this is an iffy use of map though.

---

Cor! Like yer ring! ... HALO dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!

Your map is in void context, it is not used for anything but a fancy loop. I think the logic of the @maxreject array is flawed, but I'm not sure what you're trying to accomplish with it.

I suspect you want (split ' ') where you break a line into an array.

Update: Ah, in that case, I'd keep an array of the column indexes to tag (supposing there may be more than one) and do this:

my @tagthese = (4,5,6);
# ... down in the read loop
    for (@data[@tagthese]) {
        $_ = '?' . $_ if $_ < $minclip or $_ > $maxclip;
    }
[download]

After Compline,
Zaxo

The idea behind the @maxreject array is that is a user to rejects values associated with a column, they click a checkbox on the form and the value for that column becomes true. If the value is greater or less than a user-defined value, the value of the column is flagged.
Stacy.