ENH: DataFrame.from_xy methods are duplicates

[alefnula]

Decide what to do with each of these

• deprecate from_csv / change to be exactly like read_csv -> DEPR: Deprecate from_csv in favor of read_csv #17812
• from_dict
• from_records (see Extremely slow construction of large DataFrames out of ndarrays? #8161)
• from_items (DEPR: Deprecate from_items #18529)

This is just a suggestion: DataFrame constructor already supports the things that from_dict and from_records do (from_items is not supported by the constructor, but maybe it should be?). Also from_csv does the same thing as pd.read_csv.

Since There should be one-- and preferably only one --obvious way to do it. maybe these methods should be removed/deprecated?

I know that this would cause backward incompatibility, so maybe just a deprecation warning could be displayed until a future major release that could remove them.

[cpcloud]

There's an issue for the from_csv somewhere...

[cpcloud]

from_csv is slightly different w.r.t parsing dates. I believe it defaults to parsing dates where as read_csv doesn't

[cpcloud]

#4191

[alefnula]

Also #3418. Yes from_csv has parse_dates=True. But this is not just about read_csv. from_dict also has an orient='columns' parameter. from_records has exclude and coerce_float, and from_items is not even supported by the constructor. This is just a suggestion for a possible unification, since the constructor already supports most of the things that those methods do.

[jreback]

from_csv is a convience method

from_records/from_items are straightforward to integrate into the constructor (I thought there was an issue about this....hmm)

from_dict is really superfluous (but used internally in places), so can easily be changed

certainly would take a PR for this, maybe just having it work in 0.13, while warning that its going to be changed in say 0.14

(and I would keep from_records as a separate method), just make it internal, same

[jreback]

@alefnula yep....its straightforward to do this actually, just add the appropriate keywords to the main DataFrame constructor and delegate if these are passed

[jtratner]

Isn't this in the Python for Data Analysis book? Not great to break examples from something that actually gets people to try pandas.

[jreback]

I think maybe starting in 0.14 should put deprecations around these (may not actually remove for a while though)....the naming scheme is quite inconsistent with everything else

[jorisvandenbossche]

I think for 0.16, we should at least just deprecate from_csv. That is not much work (does not need to be integrated in something else), came up again at SO: http://stackoverflow.com/questions/26495408/pandas-pandas-dataframe-from-csv-vs-pandas-read-csv/26495839#26495839