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Re^2: Format, empty vars, and fixed-width records

by kwaping (Priest)
on Apr 21, 2008 at 23:40 UTC ( #682051=note: print w/replies, xml ) Need Help??

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

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.
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Re^3: Format, empty vars, and fixed-width records
by BrowserUk (Pope) on Apr 22, 2008 at 00:14 UTC

    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

    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

    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.

      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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