根据python中嵌套词典中的键删除项目 [英] Deleting Items based on Keys in nested Dictionaries in python

问题描述

我的字典像这样:

{
    'key1': 
        {
            'a': 'key1', 
            'b': 'val1', 
            'c': 'val2'
        }, 
    'key2': 
        {
            'a': 'key2', 
            'b': 'val3', 
            'c': 'val4'
        }, 
    'key3': 
        {
            'a': 'key3', 
            'b': 'val5', 
            'c': 'val6'
        }
}

我试图根据键"a"删除嵌套字典中的元素，以得到如下输出:

I trying to delete the elements in the nested dict based on the key "a" to get an output like this:

{
    'key1': 
        {
            'b': 'val1', 
            'c': 'val2'
        }, 
    'key2': 
        {
            'b': 'val3', 
            'c': 'val4'
        }, 
    'key3': 
        {
            'b': 'val5', 
            'c': 'val6'
        }
}

我为此编写了以下代码段:

I wrote the following snippet for it:

for k in dict_to_be_deleted:
    del k["a"]

我不断收到关键错误:找不到k.我也尝试了以下方法:

I keep getting Key Error: k not found. I tried the following method as well:

for i in dict_to_be_deleted:
    for k,v in i.items():
        if "a" in k:
            del i[k]

我知道

Attribute Error: str object has no attribute items

但是因为 dict_to_be_deleted 是嵌套的字典，所以它不是应该是字典吗?我对此很困惑.我非常感谢在这方面的任何指示.

But isn't it suppose to be a dictionary since dict_to_be_deleted is a nested dictionary? I am pretty confused with this. I greatly appreciate any pointers in this regard.

推荐答案

在字典上进行迭代时， dict_to_be_deleted 仅在键上进行迭代.因此，在第二次尝试中，您的 Attribute Error 是因为 i 是键，而不是字典，是字符串.实际执行此操作的方法将是使用 .values()代替，它会遍历值.

When you're iterating over a dictionary, dict_to_be_deleted you are only iterating over the keys. So in your second attempt, your Attribute Error is because i is the key, a string not the dictionary. How you could actually perform it would be to use .values() which iterates over the values instead.

for v in dict_to_be_deleted.values():
    del v["a"]

但是，就我个人而言，我建议不要遵循删除元素的方法，而是遵循Ajax的方法并构建一个没有缺失元素的新字典.像我们在这里所做的那样的怪异突变是获取错误的简便方法.

However, personally, instead of deleting the elements, I'd suggest following Ajax's method and building a new dictionary without the missing elements. Weird mutations like what we're doing here is an easy way to get bugs.

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