http://www.perlmonks.org?node_id=1170879


in reply to Using (s)printf()

Having studied the article, I, the newest monk, still can't cipher how to print two floating-point numbers so they'll align On The Decimal, so the numbers may be added properly, pencilularly. e.g., print 0.12345 and -123456.12 to align thusly (oh, please let my spaces be preserved!): 
      0.12345
-123456.12

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I know I'm not the only monk that seeks this. There is that other fellow in Andalusia.

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Re^2: Using (s)printf()
by RichardK (Parson) on Aug 31, 2016 at 18:03 UTC

    Try this

    perl -E 'printf("%12.4f\n",12.34)'

    gives

    >     12.3400

    see the docs for sprintf for much more detail :) but in brief it's "%<length>.<dp>f"

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Re^2: Using (s)printf()
by Br'er Rabbit (Novice) on Aug 31, 2016 at 13:34 UTC
    Ahhh, but Re-studying the article, the thought arises that the answer might lie with "sprintf()", using it to convert to a string which can be fed to string-processing functions to find the location of the '.' and to identify, and reserve, the parts before and after. Perhaps?
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      Trailing whitespace can be a bit tricky. Maybe something like: 

      c:\@Work\Perl\monks>perl -wMstrict -le
"for my $n (qw(
   0.12345 -0.12345  123456.12 -123456.12  123456.12345 -123456.12345
   )) {
   my ($left, $right) = (7, 5);
   my $s = sprintf qq{%${left}s.%-${right}s}, split m{[.]}xms, $n, 2;
   print qq{'$s'};
   }
"
'      0.12345'
'     -0.12345'
' 123456.12   '
'-123456.12   '
' 123456.12345'
'-123456.12345'

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      Give a man a fish:  <%-{-{-{-<

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