CLN: Simplify Period Construction / Resolution

[sinhrks]

Simplified Period construction a little by adding millisecond resolution.

[jreback]

I not sure this is tested but in theory an older pickle will break as these codes have changed
can u preserve the original codes (and just add the new one)?

[sinhrks]

Ah, I thought this is not stored as property. Modified.

[jreback]

no make it 5
these are just enums

[sinhrks]

No, it should have order for comparison. How should the value be?
https://github.com/pydata/pandas/blob/master/pandas/tseries/index.py#L1172

[jreback]

modify this to add Period/PeriodIndex https://github.com/pydata/pandas/blob/master/pandas/io/tests/generate_legacy_pickles.py

run it on 0.14.0 and add generated pickles to the repo
then test with this change to see if pickle works ok (if u can do more than 1 version/platform would be gr8)

[jreback]

if u want to add some for prior versions of pandas ok too (this scipy is meant to be independent of pandas versions for this reason)

the test suite will test the pickles on current version for back compat tests

[sinhrks]

Thanks. As Period can't be pickled, going to confirm PeriodIndex only.

import pickle
pickle.dumps(pd.Period('2011-01-01'))
# TypeError: a class that defines __slots__ without defining __getstate__ cannot be pickled

[jreback]

ahh right.....that is a separate issue (and should be resolved as well)

[sinhrks]

OK. Added PeriodIndex pickles taken in 0.13.0 and 0.14.0.

[jreback]

gr8 thanks!