Python: Datetime to season

Question

I want to convert a date time series to season, for example for months 3, 4, 5 I want to replace them with 2 (spring); for months 6, 7, 8 I want to replace them with 3 (summ

Answer 1

It's, also, possible to use dictionary mapping.

1. Create a dictionary that maps a month to a season:

   In [27]: seasons = [1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 1]
   
   In [28]: month_to_season = dict(zip(range(1,13), seasons))
   
   In [29]: month_to_season 
   Out[29]: {1: 1, 2: 1, 3: 2, 4: 2, 5: 2, 6: 3, 7: 3, 8: 3, 9: 4, 10: 4, 11: 4, 12: 1}
   

2. Use it to convert the months to seasons

   In [30]: df.id.dt.month.map(month_to_season) 
   Out[30]: 
   1    3
   2    3
   3    3
   4    4
   5    4
   6    4
   7    4
   8    4
   Name: id, dtype: int64
   

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Performance: This is fairly fast

In [35]: %timeit df.id.dt.month.map(month_to_season) 
1000 loops, best of 3: 422 µs per loop