How to get Year Mont and Quarter from time series in python

I have this dataset:

And I want to separate date_time into: YM (Year_Month),YMQ(Year_Month_Quarter),Y and M:

I already succeeded with separating it with YM,Y and M with this code:

list_YM = [i.split(" ")[0][:-3] for i in  list(train_dataset['date_time'])]
list_Year = [i.split(" ")[0][0:4] for i in  list(train_dataset['date_time'])]
list_Month = [i.split(" ")[0][5:7] for i in  list(train_dataset['date_time'])]

train_dataset['YM'] = list_YM
train_dataset['Year'] = list_Year
train_dataset['Month'] = list_Month

But how do I get YMQ and Q?

>Solution :

If you already have the months listed in list_Month, then you can use a simple floored integer division to get the corresponding quarter of each month:

list_quarter = [(((i - 1) // 3) + 1) for i in list_Month]

This works because the result of this integer division will be zero for months 1, 2 and 3; 1 for months 4, 5, and 6; 2 for months 7, 8, and 9; and 3 for months 10, 11 and 12.

For YMQ you simply concatenate Y, M and Q, which you already have.