在Python中更新字典词典 [英] Updating Dictionary of Dictionaries in Python

问题描述

我基本上是在一个CSV文件中读取，并创建一个名为City的对象，该对象使用传递给构造函数city_constructor的属性创建。 编辑：文件每行都有城市信息。我有一个我正在努力更新的命令，其中包含与两个不同类别相关联的关键值：

 ％d是一个从dictReader = csv.DictReader（placesFile）获得的迭代器
％定义我的命令名为place 
 places = {City：{}，Country：{}} 
  

然后我尝试将新对象添加到我的dict命令中，如下所示，但这似乎没有工作。有没有办法做到这一点？在dictReader中的
new_City = city_constructor（d [人口 ]，d [Area]）
places.update（{City：new_City}）

解决方案

您应该可以更新您的地方字典：

  place [City] = new_City 
  

如果你的文件在每一行都有City信息，那么我猜你会在做$ code> new_City = city_constructor（d [Population]，d [Area]）在每一行。在这种情况下，您的位置应该如下所示：

  places = { City：[]，Country：[]} 
  

  for d在dictReader中：
 new_City = city_constructor（d [人口]，d [区域] ）
 place [City]。append（new_City）
  

如果必须一个简单的例子，那么你的地方应该是这样的：

  {
City：{
City_1：< city_constructor（d [人口]，d [区域]）第一行> 
City_2 < city_constructor（d [Population]，d [Area]）第二行> 
City_3：< city_constructor（d [Population]，d [Area]）第三行> 
} 
} 
  

就是说，与一个新城市遇到的每一行相关联的新密钥。可能是这样的：

  count = 0 
 for d在dictReader中：
 new_City = city_constructor d [人口]，d [区域]）
 _a_dict = {'City _ {}'。format（count）：new_City} 
 count + = 1 
 places [City ] .update（_a_dict）
  

I'm essentially reading in a CSV File and am creating an Object called "City" which is created using attributes passed to the constructor "city_constructor". Edit: The file has "City" information on every line. I have a dict of dicts which I am struggling to update, which takes in key values associated with 2 different Classes:

% d is an iterator obtained from dictReader = csv.DictReader(placesFile)
% Defining my dict of dicts called places
places = {"City":{}, "Country":{}}

And I then try and add the new object into my dict of dicts as follows, but this does not appear to be working. Is there a way to do this?:

for d in dictReader:
    new_City = city_constructor(d["Population"],d["Area"])
    places.update({"City":new_City})

解决方案

You should be able to update your places dictionary with:

places["City"] = new_City

If your file has "City" information on every line, then I am guessing you would be doing new_City = city_constructor(d["Population"],d["Area"]) on every line. In that case, your places should be like:

places = {"City":[], "Country":[]}

And you would update it as:

for d in dictReader:
    new_City = city_constructor(d["Population"],d["Area"])
    places["City"].append(new_City)

If it has to be a dict of dicts, then your places should be structured something like:

{
    "City": {
        "City_1": <city_constructor(d["Population"],d["Area"]) of first line>,
        "City_2": <city_constructor(d["Population"],d["Area"]) of second line>,
        "City_3": <city_constructor(d["Population"],d["Area"]) of third line>,
    }
}

That is, there has to be a new key associated with every line a new city is encountered. May be something like this:

count = 0
for d in dictReader:
    new_City = city_constructor(d["Population"],d["Area"])
    _a_dict = {'City_{}'.format(count):new_City}
    count += 1
    places["City"].update(_a_dict)

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