in reply to Format, empty vars, and fixed-width records

I also tried using sprintf, but if the data is longer than intended, the line becomes too long.

You do know you can specify the maximum width? 

printf "%2.2s>%32.32s<\n", 
    $_, 'x' x $_ for 30 .. 34, 99..101;;
30>  xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx<
31> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx<
32>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx<
33>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx<
34>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx<
99>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx<
10>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx<
10>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx<

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Re^2: Format, empty vars, and fixed-width records
by kwaping (Priest) on Apr 21, 2008 at 23:40 UTC
    Thank you for mentioning that, as I did not know about that detail. However, after reading the perldoc on it, I don't believe that will limit the lengths of my numeric fields, which may be a problem.

    ---
    It's all fine and dandy until someone has to look at the code.
[reply]

      As I showed with the decimal field at the beginning of the records above, you can truncate integer fields by using %N.Ns. Unfortunately, the truncation always occurs on the right regardless of whether you use '-' or not: 

      [0] Perl> printf "%2.2s\n", $_ for 9, 99 .. 101;;
 9
99
10
10
[0] Perl> printf "%-2.2s\n", $_ for 9, 99 .. 101;;
9
99
10
10

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      Which may not be what you want. The real problem (sic) is floating point numbers, there's just no sensible way to squeeze them into a fixed width field if they stray beyond a limited range: 

      printf "%-8.8s\n", sprintf '%8f', $_ 
    for map{ 1.23456789 * $_} map{ "1e$_" } -10 .. 10;;
0.000000
0.000000
0.000000
0.000000
0.000001
0.000012
0.000123
0.001235
0.012346
0.123457
1.234568
12.34567
123.4567
1234.567
12345.67
123456.7
1234567.
12345678
12345678
12345678
12345678

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      And its worse if you want or need to maintain point alignment.

      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
[select]

        You could handle number overflow like Excel does: 

        sub format_num { 
   my $s = sprintf('%5.2f', $_[0]);
   return length($s) > 5 ? 'XXXXX' : $s;
}

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[d/l]

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