In [33]:
import numpy as np

Let's create a small dataframe to understand the log transformation

In [34]:
df = pd.DataFrame({"d" : [1, 10, 1000]})
In [35]:
df
Out[35]:
d
0 1
1 10
2 1000
In [36]:
df['log(10)d'] = np.log10(df['d'])
In [37]:
df
Out[37]:
d log(10)d
0 1 0.0
1 10 1.0
2 1000 3.0