in reply to Integer vs Float during addition

Actually, that was a cleaned-up example, the actual one was using 
if( $cost) 
{
    ....
}

[download]
but I was getting different results (ie if() was true/false) depending on whether the $cost of 0.00 was extracted via DBI::MYSQL and then left untouched, or extracted via DBI::MYSQL and then added to an integer zero.
Took me a while to figure out why the optional code path was /was not being followed.
ie not just an academic qn and nothing to do with printing as such.
Cheers
Chris

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Re^2: Integer vs Float during addition
by Zaxo (Archbishop) on Jun 29, 2006 at 04:39 UTC

    Ok, you took it the opposite direction. Boolean context doesn't force anything. Print forces to string. 0+ forces to number.

    The string '0.00' is true, but numeric zero is false.

    After Compline,
    Zaxo

[reply]
      More specifically, string '0.00' is true but string '0' is false. This tends to surprise C-to-Perl newcomers. So if someone got a string and they weren't sure if it was natural or sprintf-formatted, it could lead to bugs in logic. 
      use Data::Dumper;
for (0, '', '0', '00', '0.0', '0.00', undef) {
    print (($_? 'TRUE' : 'FALSE'), ': ', Dumper($_));
}

      [download]

      --
      [ e d @ h a l l e y . c c ]

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Re^2: Integer vs Float during addition
by Moron (Curate) on Jun 29, 2006 at 12:41 UTC
    One way to do that is:
    if ( NumericTrue( $cost ) ) {
    ...
}

sub NumericTrue{
    return shift()*1.0;
}

    [download]
    (Updated to allow e.g. 99 cents to be a cost.)

    -M

    Free your mind

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[d/l]
      Or return 0+shift();
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[d/l]

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