Assigning a value to a pandas column by Iterating through lists

Question

I have a three-part question - I have three lists and I'm trying to write a loop to iterate over either two of lists to assign a value to a new column based on a match (or through the list of lists). When I assign it to the column like below it only prints the else value or whatever number in the last condition. Thank you in advance.

Why is that?
How do I format this loop?

Can someone write a better for loop that iterates over all_names assigning 1 to a match from all_names[0] and 2 for a match all_names[1]? - does enumerate work for that?

first_names = ['David', 'Dani', 'Declan']
second_names = ['Katz', 'Foley', 'Stevenson']
all_names = [first_names, second_names]

for row in df['name']:
    for elem in firstname_list:
       if elem in row:
          df['name_num']= 1
    for elem in secondname_list:
       if elem in row:
          df['name_num']= 2
    else:
         df['name_num']= 3

score 1 · Accepted Answer · answered Feb 09 '21 at 22:03

1

Check with np.select:

df['name_num'] = np.select( (df['name'].isin(first_names), 
                             df['name'].isin(second_names) ),
                            (1,2), 3)

answered Feb 09 '21 at 22:03

Quang Hoang

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Im think something like this for elem_a in first_name, for elem_b in second_name if elem_a is in row df[name_num] = 1 if elem_b is in row df[name_num] =2 – Digital Moniker Feb 09 '21 at 22:04
Okay @Quang Ill try that in a minute, thanks! – Digital Moniker Feb 09 '21 at 22:05
is it possible to modify this to provide a match based on a partial match? e.g. I have Dani but would like it to match Danielle also – Digital Moniker Feb 09 '21 at 22:18
1

Replace `isin` with answer in [this question](https://stackoverflow.com/questions/26577516/how-to-test-if-a-string-contains-one-of-the-substrings-in-a-list-in-pandas). – Quang Hoang Feb 09 '21 at 22:19
Ahh I had tried with just .str.contains but not the |.join(list) thank you very much sir. – Digital Moniker Feb 09 '21 at 22:23

Assigning a value to a pandas column by Iterating through lists

1 Answers1