if I have a data set of time series and I want to estimate the number of the day of a groupby time series per each day as seen in the figure and act as a counter :
nothing special in my code yet, it is just reading the data and convert time and day into
import pandas as pd
df = pd.read_csv('*file location and name*',sep=",")
df.head()
df['Date'] =pd.to_datetime(df['Date']+" "+df['Time'])
df.set_index('Date', inplace=True)