如何查找和添加ID的频次列？

Question

I am a beginner at python, so bear with me!

My dataset is from excel and I was curious how to find and add a frequency column for my ID.

I first performed the groupby function for ID and date by doing:

dfcount = dfxyz.groupby(["ID", "Date"])

and then found the mean by doing:

dfcount1 = dfcount.mean()

The output i got was:

What I am trying to do is get the frequency number beside it like this:

I did not know how to copy python code, so I uploaded pictures! Sorry! Any help is appreciated for what code I can use to count the frequency for each ID AFTER I find the mean of the groupby columns.

Thank you in advance!

Answer 1

您可以将cumcount与groupby一起cumcount

df['Freq']=(df.groupby(level=0).cumcount()+1).values

Answer 2

You can use this:

df['column_name'].value_counts()

value_counts - Returns object containing counts of unique values