関連ワード:  python dataframe replace nan with previous value    python dataframe fill nan with previous value    python pandas fill nan with previous value    pandas dataframe replace nan with previous value    python dataframe replace nan with value    pandas dataframe fill nan with previous value    python pandas replace nan with value    python pandas replace nan with value from another column    pandas fill nan with previous value    pandas replace nan with last value  
結果 : python dataframe replace nan with previous value