for time in df['日期']):
? ? print(time.date())

def DateSplit(df, col):
    """
    split the object of '2010-01-02' into year(2010), month(1) and day(2).
    :param df:  to operate data （type：DataFrame）
    :param col: column label of date object （type：str）
    :return: converted date （type： DataFrame）
    """
    year, month, day = [], [], []
    data = df.loc[:, col].values
    df = df.drop([col], axis=1)
    
    for i in range(data.shape[0]):
        year.append(int(data[i][:4]))
        month.append(int(data[i][5:7]))
        day.append(int(data[i][8:]))
    date = pd.DataFrame({'year': year, 'month': month, 'day': day})
    result = pd.concat([date, df], axis=1)
    return result
 
 
pm25_train = pd.read_csv("./datasets_PM25/pm25_train.csv")
data= DateSplit(df=pm25_train,col='date')
data.head(10)