Need to autofill values based on another column

[Chicago2Nashville00]

Hello all I'm wondering how I would auto fill based on another value. 

For example below is how the data comes in 

1	Cat
1
2
2	Dog
3	Rabbit
3

There are more numbers and text but I'm looking for the data to look like this 

1	Cat
1	Cat
2	Dog
2	Dog
3	Rabbit
3	Rabbit

Thank you all

[arindita97]

Hi,

try to use multi-row formula to perform this task. I've mentioned the logic in the image.

[Chicago2Nashville00]

Hi! thank you for the reply. Apologies i should have mentioned that the 2nd and 1st column are related so 1-> Cat , 2->Dog, 3-> Rabbit. It's not always a down fill sometimes like in row 3 and 4 it's above it. Hopefully that makes sense. 

[Qiu · Accepted solution]

@Chicago2Nashville00 
So we can filter the Non-Null value for the names then do a join with null value with key as "1, 2,3"?

[Chicago2Nashville00]

thank you!

[Qiu]

@Chicago2Nashville00 

Glad it helps a bit.