根据其他列的值填充熊猫列的简便方法

Question

I have a pandas DataFrame with 3 columns like this:

      a   b   c
0      1  1  10
1     2  12  10
2    16  13  10
3      9 16  10

In column c I would like to have the maximum of the 3 numbers in each row, so It should look like this:

      a   b   c
0      1  1  10
1     2  12  12
2    16  13  16
3      9 16  16

I could do this with for loops, but I was wondering if there is any simpler way to do this?

Answer 1

Use df.max(axis=1)

In [1807]: df['c'] = df.max(axis=1)

In [1808]: df
Out[1808]:
    a   b   c
0   1   1  10
1   2  12  12
2  16  13  16
3   9  16  16

---

Or, assign to return new dataframe

In [1812]: df.assign(c=df.max(axis=1))
Out[1812]:
    a   b   c
0   1   1  10
1   2  12  12
2  16  13  16
3   9  16  16