identify the columns have specific value for each row in python

Question

I'm newer at python. I have a dataframe like this

            1   2   3   
 75016      1   2   2   
 75017      0   0   0       
 75018      0   2   2   

For each row, I want to identify what the columns have the value = 1 or 2 the output =

" 75016 " has = column 1,2,3
" 75017 " has column
" 75018 " has column 2,3

how I can do it? thank you

Answer 1

Assuming a pandas DataFrame, you can use:

s = df.stack().isin([1,2])
out = (s[s]
       .reset_index(1)
       .groupby(level=0)['level_1']
       .agg(','.join)
       .reindex(df.index).fillna('')
      )

output:

75016    1,2,3
75017         
75018      2,3
Name: level_1, dtype: object

used input:

import pandas as pd
df = pd.DataFrame({'1': [1, 0, 0], '2': [2, 0, 2], '3': [2, 0, 2]},
                  index=[75016, 75017, 75018])