Python 如果然后是结构以及如何跨多行应用

我有一个数据框，包含3列：邮政编码、自治区和邻里区，共257行。你可以暂时忘记邮政编码

对于自治区和邻里区，任何一列都可能已经添加了有效的位置，或者没有被指定，我正在尝试找出如何执行以下操作。如果一个单元有一个有效的自治区位置，可以是任何东西，但未指定该邻域，则该邻域将被设置为与该自治区相同。 所以逻辑是这样的：

 If Neighbourhood="Not Assigned" AND Borough<>"Not Assigned" then Neighbourhood=Borough
    Repeat for all rows

使用pandas库，我们可以对数据帧使用子集技术

首先，出于测试目的，我重新创建了只包含两列的数据帧：Borough和neighbourth。我还添加了另一行，因为提供的数据都不符合条件

borough = ["Not assigned", "Not assigned", "Not assigned", "Not assigned", "Etobicoke", "Etobicoke", "Etobicoke", "Etobicoke", "Etobicoke", "Not assigned", "Etobicoke"]
neighbourhood = ["Not assigned", "Not assigned", "Not assigned", "Not assigned", "Kingsway Park South West", "Mimico NW", "The Queensway West", "Royal York South West", "South of Bloor", "Not assigned", "Not assigned"]

df = pd.DataFrame({"Borough": borough,
                   "Neighbourhood": neighbourhood})
print(df)

然后我们创建一个条件语句：如果一个单元有一个有效的自治区位置，可以是任何东西，并且没有指定邻域，那么邻域将被设置为与自治区相同

条件是一个布尔序列，它只包含True和False，用于对数据帧进行子集设置

最后，如果行满足条件，我们用Borough列中的值替换neighbour列中的值

borough = ["Not assigned", "Not assigned", "Not assigned", "Not assigned", "Etobicoke", "Etobicoke", "Etobicoke", "Etobicoke", "Etobicoke", "Not assigned", "Etobicoke"]
neighbourhood = ["Not assigned", "Not assigned", "Not assigned", "Not assigned", "Kingsway Park South West", "Mimico NW", "The Queensway West", "Royal York South West", "South of Bloor", "Not assigned", "Not assigned"]

df = pd.DataFrame({"Borough": borough,
                   "Neighbourhood": neighbourhood})
print(df)

或者，您也可以执行循环，但这不是一个好的做法，因为对于较大的数据，计算速度可能较慢：

for idx, row in df.iterrows():
    condition = (row["Borough"] != "Not assigned") & (row["Neighbourhood"] == "Not assigned")
    if condition:
        row["Neighbourhood"] = row["Borough"]

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你能提供你的python代码吗？在python中，如果。。。那就是如果…：。请避免指出您是初学者以及其他与您的问题无关的短语，因为它们只是分散注意力，例如，如果您是初学者或专家，我们不感兴趣，而是问题本身。

for idx, row in df.iterrows():
    condition = (row["Borough"] != "Not assigned") & (row["Neighbourhood"] == "Not assigned")
    if condition:
        row["Neighbourhood"] = row["Borough"]