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Supressing zero values in formatted reports

by ryan (Pilgrim)
on Dec 28, 2001 at 13:18 UTC ( #134831=perlquestion: print w/ replies, xml ) Need Help??
ryan has asked for the wisdom of the Perl Monks concerning the following question:

I am using formatting to output some information, I was wishing to supress the display of all zero (0) values.

Setting the variables concerned to blank '' or undefing them only causes errors.
format top = User Emails Size (Kb) ============== ======== =========== . format DISPLAY = @<<<<<<<<<<<<< @#### @#####.## $output[$i], $output[$i+1], $output[$i+2]/1024 .
Can it be done?

Thanks ... Ryan

Comment on Supressing zero values in formatted reports
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Re: Supressing zero values in formatted reports
by Fengor (Pilgrim) on Dec 28, 2001 at 14:04 UTC
    From the perfunc page of format:
    format Something = Test: @<<<<<<<< @||||| @>>>>> $str, $%, '$' . int($num) . $str = "widget"; $num = $cost/$quantity; $~ = 'Something'; write;
    so maybe u can do something like:
    format top = User Emails Size (Kb) ============== ======== =========== . format DISPLAY = @<<<<<<<<<<<<< @#### @#####.## $temp[$i], $temp[$i+1], $temp[$i+2] . if ($output[$i]) {$temp[$i]=$output[$i]} else {$temp[$i]==' '} if ($output[$i+1]) {$temp[$i+1]=$output[$i+1]} else {$temp[$i+1]==' '} if ($output[$i+2]) {$temp[$i+2]=$output[$i+2]/1024} else {$temp[$i+2]==' '}
    hth
    fengor

    --
    "WHAT CAN THE HARVEST HOPE FOR IF NOT THE CARE OF THE REAPER MAN"
    -- Terry Pratchett, "Reaper Man"

      Thanks, however that causes the same Argument " " isn't numeric in formline error that setting it to blank does.
        Hmm this isn't an error. It's a warning.

        From perldiag: Argument "%s" isn't numeric%s

        (W) The indicated string was fed as an argument to an operator that expected a numeric value instead. If you're fortunate the message will identify which operator was so unfortunate.

        This means although the warning is displayed your program should run normally.

        hth
        fengor

        --
        "WHAT CAN THE HARVEST HOPE FOR IF NOT THE CARE OF THE REAPER MAN"
        -- Terry Pratchett, "Reaper Man"

Re: Supressing zero values in formatted reports
by robin (Chaplain) on Dec 28, 2001 at 15:41 UTC
    From the perlform manpage:
    Picture fields that begin with ^ rather than @ are treated specially. With a # field, the field is blanked out if the value is undefined. For other field types, the caret enables a kind of fill mode.
    So change your @#### to ^####, and make sure the values you want to suppress are undefined.

    The second problem is that using an undefined value when warnings are enabled will generate several warning messages. I suggest disabling warnings within the format, like this:

    { no warnings; format STDOUT = @<<<<<<<<<<<<< ^#### @#####.## $output[$i], $output[$i+1], $output[$i+2]/1024 . }
      hmm guess i should read more carefully next time ;-)

      thx
      fengor

      --
      "WHAT CAN THE HARVEST HOPE FOR IF NOT THE CARE OF THE REAPER MAN"
      -- Terry Pratchett, "Reaper Man"

      That works, thanks for that, I must try to search more for the answers for these things. I did a lot of searching in the wrong places :)

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