Multiply all columns in a Pandas dataframe together

Question

Is it possible to multiply all the columns in a Pandas.DataFrame together to get a single value for every row in the DataFrame?

As an example, using

df = pd.DataFrame(np.random.randn(5,3)*10)

I want a new DataFrame df2 where df2.ix[x,0] will have the value of df.ix[x,0] * df.ix[x,1] * df.ix[x,2].

However I do not want to hardcode this, how can I use a loop to achieve this?

I found a function df.mul(series, axis=1) but cant figure out a way to use this for my purpose.

Answer 1

You could use DataFrame.prod():

>>> df = pd.DataFrame(np.random.randint(1, 10, (5, 3)))
>>> df
   0  1  2
0  7  7  5
1  1  8  6
2  4  8  4
3  2  9  5
4  3  8  7
>>> df.prod(axis=1)
0    245
1     48
2    128
3     90
4    168
dtype: int64

You could also apply np.prod, which is what I'd originally done, but usually when available the direct methods are faster.

>>> df = pd.DataFrame(np.random.randint(1, 10, (5, 3)))
>>> df
   0  1  2
0  9  3  3
1  8  5  4
2  3  6  7
3  9  8  5
4  7  1  2
>>> df.apply(np.prod, axis=1)
0     81
1    160
2    126
3    360
4     14
dtype: int64