in reply to Weird number formatting

Maybe I'm missing something, but shouldn't it be "0.225150000000000E+06"? ("E" instead of "D")? Or is that some locale settings?

Also, just a side note, do you really want 9999 entries in @info, or do you just want to split however many there are? If so, just omit the 3rd paramater to split.

-- zigdon

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Re^2: Weird number formatting (FORTRAN double)
by tye (Sage) on Mar 05, 2003 at 19:14 UTC

    The 'D' means that the values are doubles instead of floats (in FORTRAN).

    Updates:

    This sounds like a bug that should be reported to p5p. This is such an old and standard notation that it will probably be common for C's strtod() to support it so Perl should be made aware of it in order to avoid the misleading warning.

    split didn't used to support -1 as the third argument so old code had to make up some "arbitrarilly large number" to get such functionality. In this case, I would think just dropping the third argument makes the most sense (since trailing spaces should probably not create a final, empty "number" to be processed). But in other cases you should change the "9999" to "-1" so that your code won't break when you actually get 10000 items. I complained about this in Perl 4 and suggested the current behavior but Larry didn't seem impressed so I was glad when this feature showed up. (:

                    - tye
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Re: (z) Re: Weird number formatting
by licking9Volts (Pilgrim) on Mar 05, 2003 at 18:00 UTC
    I thought the same thing about the E instead of D, but the files are USGS Digital Elevation Models taken from the Texas National Resources Information website. DEM is some kind of standard format for these models. Thanks for the tip on splitting also. I've fixed it.
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      See, you need one of us old-timers for this kind of stuff. ;-)

      In all likelihood, a Fortran program is producing that data. The variable in the program is declared DOUBLE PRECISION, and probably a D or G format is being used to print it. Just substitute E for D and you should be fine.

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      Surely, surely, those 'D's have to mean 'E's... well, of course they don't have to, but if you have to add 30 to one of those numbers, then you have to know what the original number is, right?

      So that's a piece of data you need someone to inform you of. If it is an exponent indicator, then can you just do a pattern match before interpreting the number (s/D/E/)?

      Rob
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        Maybe I'm missing something...

        What I don't get is that the addition is performed correctly despite the "D" instead of "E". 
             $my_x = $info[4] + 0;
     $my_y = $info[5] + 30;
     for($i = '1'; $i <= $info[2]; $i++) {
          print ("$my_x $my_y $info[($i + 8)]\n");
          $my_y = $my_y + 30;

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        I would expect to see for the output: 
        0.22512 30.341916 661

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        but it actually does understand D+06 as exponential notation
        Can anyone explain why?

        Thanks,
        Kris
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