Iterating A Pandas Dataframe Over 'n' Next Rows

I have this Pandas dataframe df: station a_d direction a 0 0 a 0 0 a 1 0 a 0 0 a 1 0 b 0 0 b 1 0

Solution 1:

You are not effectively using z in the inner for loop. You never access the i+z-th row. You access the i-th row and the i+1-th row and the i+2-th row, but never the i+z-th row.

You can replace that inner for loop with:

if i+1 > len(df)-1:
    passelif (df.loc[i+1,'a_d'] == df.loc [i,'a_d']):
    passelif (df.loc [i+2,'station'] == df.loc [i,'station'] and (df.loc [i+2,'direction'] == df.loc [i,'direction'])):
    passelse:
    df.loc[i,'value_id'] = value_id

Note that I also slightly optimized the second elif because at that point you already know df.loc[i+1,'a_d'] does not equal df.loc [i,'a_d'].

Not having to loop over z will save a lot of time.