Python pandas: filter columns in dataframe BEGINNING with pattern

I have 2 columns called eta and theta in a pandas data frame.

I’m trying to select the column called eta only.

So far I have tried

df.filter(like='eta')

…however this selects both eta and theta.

I’ve also tried pattern, but this is an R command:

df.filter(pattern='^eta')

>Solution :

Use the regex parameter of filter:

df.filter(regex=r'^eta')

Make sure to escape regex characters if needed, for instance if the columns start with eta.:

df.filter(regex=r'^eta\.')

If you have a doubt:

import re

target = 'eta'
df.filter(regex=fr'^{re.escape(target)}')