I would like to be able to read in data that uses scientific notation with a D instead of an E. This is possible on windows and other builds, but not on Mac OSX. 

example:
float('1.23D+04')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for float(): 1.23D+04

str->float conversions have been reworked in 2.7 and 3.1. The 'D' exponent will not on any platform starting with those versions.

So, this would be a non-platform specific feature request.

That was supposed to say:

The 'D' exponent will not work on any platform starting with those versions.

Out of curiosity, where are your data coming from?

For Python, this seems like a needless complication.  It should be simple enough to replace the 'D's with 'E's prior to passing the strings to float.

I notice that some varieties of Lisp and Scheme use 's', 'f', 'd', 'l' as the exponent marker for floats of different precisions (short, single, double, long double).  But Python only has one precision of float.

I am running python 2.5.4. While it works on linux and windows, it does not work on mac. 

Fortran doubles are output using the D notation. If I am importing a large amount of data, I would rather not do a search and replace every time before reading in the data.

Sorry, I'm -1 on this:  outside Fortran, using 'E' for the exponent marker seems to be near universal.  It just doesn't seem worth adding the extra complication to the Python code, or going through all the various places that expect an 'e' (float literals in Python source, inputs to the float function, Decimal and Fraction inputs, complex numbers, etc.) and trying to decide whether 'd' should be supported there too.

Even in Fortran, isn't it normal to output floats and doubles using the 'E' format specifier?

> I would rather not do a search and replace every time before reading in > the data.

There's no need to do a search and replace *before* reading the data:  read the data first, then have Python do the replace for you before passing each string to float:

>>> t = string.maketrans('d', 'e')
>>> '-14.235d+03'.translate(t)
'-14.235e+03'

Unless and until we implement 'd' exponents, we should add a test to make sure they don't work. That they ever worked on any platform was a surprise. 
--
Eric.

Done in r78166 (trunk), r78167 (py3k).

I'm -1 on this, too. Closing.