I have a dataframe that looks something like this: 1 2 3 'String' '' 4 X '' '' 5 X '' '' 6 7 'String' '' 1 Y '' And I want to change the Xs and Ys (put here just to visualize) to the value corresponding to the same column when the last column = 'String'. So, the Xs would become a 3, and the Y would be 7: 1 2 3 'String' '' 4 3 '' '' 5 3 '' '' 6 7 'String' '' 1 7 '' The reference value is the same until another 'parent' row comes around. So the first 3 remains until there comes another 'String' parent round. I tried generating another dataframe containing where there's 'String' and filling from idx to idx+1 with the value, but it's too slow. This is really similar to a forward fill (pd.ffill()), but not exactly, and I don't really know if it's feasible to turn my problem into a ffill() problem. Continue reading...
