Multiply rows in pandas DataFrame depending on values from c

Question

I would like to get from this:

nname	eemail	email2	email3	email4
Stan	stan@example.com	NO	stan1@example.com	NO
Danny	danny@example.com	danny1@example.com	danny2@example.com	danny3@example.com
Elle	elle@example.com	NO	NO	NO

To this:

nname	eemail
Stan	stan@example.com
Stan	stan1@example.com
Danny	danny@example.com
Danny	danny1@example.com
Danny	danny2@example.com
Danny	danny3@example.com
Elle	elle@example.com

I know I can create 4 separate DFs with name and email column, then merge all 4 and drop the ones with 'NO' but I feel there might be smarter and more dynamic solution for this.

Answer 1

result = (
    df.set_index("nname")
    .stack()
    .to_frame("eemail")
    .query("eemail != 'NO'")
    .droplevel(1)
    .reset_index()
)