用可变值熊猫填充数据框

Question

我真的希望你能提供帮助。

我正在研究以下内容，它找到了与特定房产最近的学校。

除最后一步外，一切正常。我在raw_data数据帧中定义“ Primary”字段的地方，它始终返回NaN，但是，如果我逐步执行，则变量Primary_Name确实会填充。

知道为什么会这样吗？

for index, row in raw_data.iterrows():  
    start = (row['lat'], row['long'])

    for index, row in schools.iterrows():
        schoolloc = (row['Latitude'], row['Longitude'])
        schools.loc[index,'distance'] = geopy.distance.geodesic(start, schoolloc).km

    schools.dropna()
    primary = schools.where(schools['PhaseOfEducation (name)'] == 'Primary')
    Nearest_Primary = primary[primary['distance'] == min(primary['distance'])]
    Primary_Name = Nearest_Primary.iloc[0]['EstablishmentName']
    raw_data.loc[index,'primary'] = Primary_Name