通过对每个唯一用户进行分组并为每个唯一日期添加访问次数列来对 dataframe 进行排序和排名 Python

Question

I am fairly new to Python and I am trying to add a visit number column in a list of users from my data frame.

I have a dataframe of 55 unique users specified by the 'UserID' column and a datetime column indicated by 'dateStarted' I want to create a column that for each user and each unique date there is aa visit number. The dataframe should look like:

  UserID dateStarted  visit
0      a    01/01/10      1
1      a    01/01/10      1
2      a    01/04/10      2
3      b    06/02/08      1
4      b    07/15/12      2
5      c    02/12/12      1
6      d    02/12/12      1

Answer 1

Group the dataframe by UserID and rank the values in dateStarted to assign ordinal values.

df['visit'] = df.groupby('UserID')['dateStarted'].rank(method='dense').astype(int)

---

  UserID dateStarted  visit
0      a    01/01/10      1
1      a    01/01/10      1
2      a    01/04/10      2
3      b    06/02/08      1
4      b    07/15/12      2
5      c    02/12/12      1
6      d    02/12/12      1