'Multiply rows in pandas DataFrame depending on values from c

I would like to get from this:

nname	eemail	email2	email3	email4
Stan	[email protected]	NO	[email protected]	NO
Danny	[email protected]	[email protected]	[email protected]	[email protected]
Elle	[email protected]	NO	NO	NO

To this:

nname	eemail
Stan	[email protected]
Stan	[email protected]
Danny	[email protected]
Danny	[email protected]
Danny	[email protected]
Danny	[email protected]
Elle	[email protected]

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.

Solution 1:^[1]

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

Solution 2:^[2]

Try this:

(df.mask(df.eq('NO'))
 .set_index('nname')
 .stack()
 .droplevel(1)
 .reset_index(level=0,name = 'eemail'))

Output:

   nname              eemail
0   Stan    [email protected]
1   Stan   [email protected]
2  Danny   [email protected]
3  Danny  [email protected]
4  Danny  [email protected]
5  Danny  [email protected]
6   Elle    [email protected]

Sources

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Source: Stack Overflow

Solution	Source
Solution 1	Code Different
Solution 2	rhug123

'Multiply rows in pandas DataFrame depending on values from c

Solution 1:[1]

Solution 2:[2]

Sources

Related Questions

Solution 1:^[1]

Solution 2:^[2]