여러 데이터 프레임 concat 후 인덱스 정렬하기

Concatenating several dataframes and rearranging index

 

I concatenated two dataframes but the index number was not rearranged.

The index number of the second datafram ‘rev_co’ was started again.  

How can I rearrange the index number so that I can easily handle the new datafram named ‘review’? 

We can use `ignore_index = True`,

Now the second datafram is concatenated in order:)