ENH date_range yearly frequency flag 'A' is confusing, 'Y' should be accepted

[mangecoeur]

to get a yearly frequency from date range the flag is actually freq="A" (for "Annual" i guess) rather than freq="Y" for yearly.

It would seem more consistent if it accepted "Y" as well/instead of "A", following the pattern:

hour -> hourly -> H
day -> daily -> D
week -> weekly -> W
year -> yearly -> Y

[TomAugspurger]

Anecdotally, I do freq='Y' almost every time. Same for resample.

[imih]

The referenced issue, #9312 (comment), concludes freq=Y should be an alias for freq='AS'

[imih]

Hi,
The aliases are here:
https://github.com/pandas-dev/pandas/blob/master/pandas/tseries/frequencies.py#L425

are we fine with freq='Y' being an alias for the beginning of the year while freq='A' being an alias for the end of the year?

Additionally, should other composed freqs containing 'Y' ( 'BYA', 'BYE', 'YA', 'YE') also be added?

[jreback]

so these should following the same convention as Q and M

so Y would be the same as A e.g. end of year and

YS would be year start

[gfyoung]

Reopening because the initial PR was incomplete.