Suppose I have df1:
假设我有df1:
col1 col2
Day0 'A' NaN
Day1 'B' 'C'
Day2 'C' 'A'
col1 Suppose I have df1:
假设我有df1:
col1 col2
Day0 'A' NaN
Day1 'B' 'C'
Day2 'C' 'A'
col1