Subtract two columns in dataframe

Using this as the df:

df = pd.DataFrame([["Australia", 1, 3, 5],
               ["Bambua", 12, 33, 56],
               ["Tambua", 14, 34, 58]
              ], columns=["Country", "Val1", "Val2", "Val10"]
             )

You can also do the subtraction and put it into a new column as follows.

>>>df['Val_Diff'] = df['Val10'] - df['Val1']

    Country     Val1    Val2  Val10 Val_Diff
0   Australia   1       3      5    4
1   Bambua      12      33     56   44
2   Tambua      14      34     58   44

Given the following dataframe:

df = pd.DataFrame([["Australia", 1, 3, 5],
                   ["Bambua", 12, 33, 56],
                   ["Tambua", 14, 34, 58]
                  ], columns=["Country", "Val1", "Val2", "Val10"]
                 )

It comes down to a simple broadcasting operation:

>>> df["Val1"] - df["Val10"]
0    -4
1   -44
2   -44
dtype: int64

You can do this by using lambda function and assign to new column.

df['Val10-Val1'] = df.apply(lambda x: x['Val10'] - x['Val1'], axis=1)
print df