How to select columns from dataframe by regex
Question: I have a dataframe in python pandas. The structure of the dataframe is as the
following:

    
    
       a    b    c    d1   d2   d3 
       10   14   12   44  45    78
    

I would like to select the columns which begin with d. Is there a simple way
to achieve this in python .


Answer: You can use [`DataFrame.filter`](http://pandas.pydata.org/pandas-
docs/stable/generated/pandas.DataFrame.filter.html) this way:

    
    
    import pandas as pd
    
    df = pd.DataFrame(np.array([[2,4,4],[4,3,3],[5,9,1]]),columns=['d','t','didi'])
    >>
       d  t  didi
    0  2  4     4
    1  4  3     3
    2  5  9     1
    
    df.filter(regex=("d.*"))
    
    >>
       d  didi
    0  2     4
    1  4     3
    2  5     1
    

The idea is to select columns by `regex`

