How to get difference of columns in DataFrame Pandas?

I need to get a DataFrame with column difference of column that I choose (for example the last one)

I tried using df.diff(axis=1, periods=1) will count column difference with the next column. However, I want to get difference of columns with exactly one column (last one).

>Solution :

Use DataFrame.sub for subtract by last column selected by DataFrame.iloc:

df1 = df.sub(df.iloc[:, -1], axis=0)

If need subtract by column selected by label:

df1 = df.sub(df['col'], axis=0)