[Numpy-discussion] formatting issues, locale and co

Pauli Virtanen pav@iki...
Mon Jan 12 15:51:41 CST 2009

Wed, 31 Dec 2008 13:11:02 +0900, David Cournapeau wrote:
> Thank you for working on this, Pauli. The problem on windows may not be
> specific to windows: the difference really is whether the formatting is
> done by python or the C runtime. It just happens that on Linux and Mac
> OS X, the strings are the same - but it could be different on other OS.
> I have not looked into C99, whether this is standardized or not (the
> size of exponent is, but I don't know about nan and inf).

C99 appears to specify for *printf (case-insensitive)

	nan, +nan, -nan, nan(WHATEVER), -nan(WHATEVER)
	inf, infinity, +inf, +infinity, -inf, -infinity

The fromfile/fromstring code now in `fix_float_format` branch recognizes 
all of these, independently of the platform.

There are also some roundtrip tests that check that this plays along as 
expected with your new float formatting code.

> We should also change pretty print of arrays, I think - although it is a
> change and may break things. Since that's how python represents the
> numbers, I guess we will have to change at some point.

It'd be nice to make also this behave as the rest of the float 
formatting. However, the current formatting of "Inf", "-Inf", "NaN" is OK 
as far as C99 is concerned.

Pauli Virtanen

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