[Python-Dev] iso8601 parsing (original) (raw)

Steven D'Aprano steve at pearwood.info
Wed Oct 25 17:30:57 EDT 2017

On Wed, Oct 25, 2017 at 04:32:39PM -0400, Alexander Belopolsky wrote:

On Wed, Oct 25, 2017 at 3:48 PM, Alex Walters <tritium-list at sdamon.com> wrote: > Why make parsing ISO time special?

It's not the ISO format per se that is special, but parsing of str(x). For all numeric types, int, float, complex and even fractions.Fraction, we have a roundtrip invariant T(str(x)) == x. Datetime types are a special kind of numbers, but they don't follow this established pattern. This is annoying when you deal with time series where it is common to have text files with a mix of dates, timestamps and numbers. You can write generic code to deal with ints and floats, but have to special-case anything time related.

Maybe I'm just being slow today, but I don't see how you can write "generic code" to convert text to int/float/complex/Fraction, but not times. The only difference is that instead of calling the type directly, you call the appropriate classmethod.

What am I missing?

-- Steven

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