vnpandey has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks..I want to write some number contained inside a scalar in exponential form for ex if the no is 122.34 I want it as 1.2234e(+2) when I ask it to print this scalar .. Please help...Thanks-VNPandey

Replies are listed 'Best First'.
RE: simple!!
by t0mas (Priest) on Aug 18, 2000 at 13:34 UTC
    How about:

    printf("%e",122.34);

    or if you want it exactly the way you said:
    $_=sprintf("%#1.4e",122.34);
s/e([+-])(.*)/"e($1".int($2).")"/e;
print;

    [download]


    /brother t0mas
[reply]
[d/l]
[select]
      Just to take it farther... to undo this, you could:

      s/([\.\d]+)e\(?([-+]?\d+)\)?/$1*10**$2/egi;

      [download]

      I would rather have the notation given as 1.2234e+2, simply because Perl sees that as a number. By that I mean if you:

      my $foo = 1.2234e(+2);

      [download]

      Perl will complain. If you do the following, it won't:

      my $foo = 1.2234e+2;

      [download]

      The above RE should handle both cases. This is fun though..

      $_=sprintf("%#1.4e",122.34);
print;
s/([\.\d]+)e\(?([-+]?\d+)\)?/$1*10**$2/egi;
print $/;
print;

      [download]

      Cheers,
      KM

[reply]
[d/l]
[select]
        A very nice undo regexp there...

        I agree with you KM that 1.2234e+2 is a better format for keeping and operations, but for printing (as I believe vnpandey wanted) I rather use the format that pays my bills :)


        /brother t0mas
[reply]
Re: simple!!
by davorg (Chancellor) on Aug 18, 2000 at 12:50 UTC

    You can do this kind of conversion (and a whole bunch more) using the Number::Format module from CPAN.

    Update

    Don't know why everyone's been voting this up. It originally said Date::Format which is clearly nonsense :( Thanks to merlyn for pointing it out.

    --
    <http://www.dave.org.uk>

    European Perl Conference - Sept 22/24 2000, ICA, London
    <http://www.yapc.org/Europe/>
[reply]

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