CODEWITHSUNDEEP
pythonpandas
Yonko
Yonko

Reputation: 63

How to filter one date column by weeks?

There is a problem - I created a table with dates for couple of years, and now i need to filter it by weeks (to work only with with first days of every week), but no matter how i try it doesn't work. Will be glad if you'll help me.

df1 = pd.DataFrame({"Date":pd.date_range(start='1/1/2018', end='31/12/2019')}) 
weeks = pd.date_range(df1['Date'].min(), df1['Date'].max(), freq ='W')
df1[weeks]

I could convert it into pd.DataFrame but then it won't give an error but instead it gives NaT in all rows.

Upvotes: 0

Views: 56

Answers (2)

Corralien
Corralien

Reputation: 120409

You can use the dt accessor and dayofweek:

# 6 -> Sunday, 0 -> Monday
>>> df1[df1['Date'].dt.dayofweek == 0]

          Date
0   2018-01-01
7   2018-01-08
14  2018-01-15
21  2018-01-22
28  2018-01-29
..         ...
700 2019-12-02
707 2019-12-09
714 2019-12-16
721 2019-12-23
728 2019-12-30

[105 rows x 1 columns]

Upvotes: 1

Mabel Villalba
Mabel Villalba

Reputation: 2598

You can do it easily just by selecting all the Mondays:

df1[lambda x: x["Date"].dt.day_name() == "Monday"]

          Date
0   2018-01-01
7   2018-01-08
14  2018-01-15
21  2018-01-22
28  2018-01-29
..         ...
700 2019-12-02
707 2019-12-09
714 2019-12-16
721 2019-12-23
728 2019-12-30

Upvotes: 2

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