Pandas: get column indices from a list of given names

Question

Let say you have a pandas dataframe input and a list of column names. What is a good way to get a list of indices (column numbers) for the columns represented by those names?

I assume it'd be something along the lines of:

def get_col_indices(df, names):
    return [df.columns.index(name) for name in names]

Answer 1

Use Index.get_indexer :

def get_col_indices(df, names):
    return df.columns.get_indexer(names)

Answer 2

If you don't need them to be in the same order, you could use pd.Index.isin with np.flatnonzero

import numpy as np
np.flatnonzero(df.columns.isin(names))