How to extract a subset of dataframe based on the last occurence of a string in a column in pandas?

I would find Sta's last occurrence and use it as the slicing parameter. There's an interesting function I didn't know that I found out working out this answer, last_valid_index() might be really helpful here.

filtered = df.loc[:df[df['name']=='Sta'].last_valid_index(),:]

 first, *_, last = df.index[df.name.eq('Sta')]
df.loc[first:last]

   ID   name  number
0   1    Sta       2
1   1  Danny       5
2   1    Sta       2
3   1   elle       4
4   1    Sta       2

Get the first and last labels for Sta and index df

staRows = df.loc[df.name == "Sta", :]
lastStA = staRows.tail()
lastStaLoc = df.index[lastSta]
final = df.loc[0:lastStaLoc]

altFinal = df.loc[0:df.index[df.loc[df.name == "Sta", :].tail()]]

staRows is every row where name is Sta

lastSta is the last row in staRows

lastStaLoc is the location of lastSta

final should be rows up to lastStaLoc

altFinal is the one line solution if you want to be fancy. This is all untested so you may have to debug a bit :)

Let us do groupby with transform idxmax

df[df.index<=df['name'].eq('Sta').iloc[::-1].groupby(df['ID']).transform('idxmax')]
   ID   name  number
0   1    Sta       2
1   1  Danny       5
2   1    Sta       2
3   1   elle       4
4   1    Sta       2