How to assign a value to the last value of a column is the easiest?-CodePudding

df = pd.DataFrame(np.zeros((6, 2)), columns=['A', 'B'])

I want to assign a value to the last value of column B. In addition to the following two methods, is there an easier way?

df.at[df.index[-1], 'B'] = 1

df.loc[df.index[-1], 'B'] = 1

CodePudding user response：

If you know the index of column B then,

df.iloc[-1,1] = 1

Else,

df.iloc[-1].B = 1

CodePudding user response：

This is a mixture of labeled indexing and indexed indexing, so I your solutions are nice already, but you could do:

df.iloc[-1, df.columns.get_loc('B')] = 1

Which is pretty neat, but it might be long but it's just the function name that's long.

Or why not just?

df.iloc[-1]['B'] = 1