pandas, multiply all the numeric values in the data frame by a constant

Question

How to multiply all the numeric values in the data frame by a constant without having to specify column names explicitly? Example:

In [13]: df = pd.DataFrame         


        

Answer 1

This should work even over mixed types within columns but is likely slow over large dataframes.

def mul(x, y):
    try:
        return pd.to_numeric(x) * y
    except:
        return x

df.applymap(lambda x: mul(x, 3))