Vectorized year/month/day operations with NumPy datetime64

Question

I would like to create vectors of NumPy datetime64 objects from 1-D vectors of years, months, and days, and also go the reverse direction, that is extracting vectors of year

Answer 1

import numpy as np
def compose_date(years, months=1, days=1, weeks=None, hours=None, minutes=None,
              seconds=None, milliseconds=None, microseconds=None, nanoseconds=None):
    years = np.asarray(years) - 1970
    months = np.asarray(months) - 1
    days = np.asarray(days) - 1
    types = ('

yields

array(['1990-01-03', '1992-06-20', '1995-03-14', '1994-07-27'], dtype='datetime64[D]')