Convert freq string to DateOffset in pandas

问题

In pandas documentation one can read "Under the hood, these frequency strings are being translated into an instance of pandas DateOffset" when speaking of freq string such as "W" or "W-SUN".

Then, how can I get an instance of a DateOffset given a string ? Ultimately want to configure my program with frequency as string (say "W-SUN"), but internally want to do something like

offset = Week(weekday=0)
if d1-3*offset<d2:
    pass

but defining offset from string.

Thanks

回答1:

You could use the to_offset function for this, although this is a rather internal pandas function (so possibly no backwards compatibility guaranteed). Some examples:

In [12]: pd.tseries.frequencies.to_offset('4Min')
Out[12]: <4 * Minutes>

In [13]: pd.tseries.frequencies.to_offset('W-SUN')
Out[13]: <Week: weekday=6>

来源：https://stackoverflow.com/questions/27368265/convert-freq-string-to-dateoffset-in-pandas