嵌套字典中的查找键

问题描述 投票:1回答:1

我正在尝试在嵌套字典中查找键:

mydict = {
    ('Geography', 1): {},
    ('Languages', 2): {
        ('English', 3): {
            ('Grammar', 6): {
                ('new', 10):{},
                ('old', 11): {}
            }
        },
        ('Spanish', 4): {},
        ('French', 5):  {
            ('Grammar', 7): {}
        },
        ('Dutch', 8): {
            ('Grammar', 9): {
                ('new', 12):{}
            }
        }
    }
}

因此,我在字典中循环查找关键字('Grammar', 9)

def _loop(topic, topics_dict):
    if (topic[0], topic[1]) in topics_dict.keys():
        return topics_dict[(topic[0], topic[1])]
    else:
        for k, v in topics_dict.items():
            if v != {}:
                return _loop(topic, v)

topic = ('Grammar', 9)
trim_mydict = _loop(topic, mydict)
print(trim_mydict)

但是,实际上,它返回None而不是{('new', 12):{}}

我已经检查了该线程(Finding a key recursively in a dictionary),但似乎正在做完全相同的事情...

python nested-loops
1个回答
1
投票

当循环中没有条件返回时,即使结果为None,它也只会返回第一个结果。我添加了这样的支票:

mydict = {
    ('Geography', 1): {},
    ('Languages', 2): {
        ('English', 3): {
            ('Grammar', 6): {
                ('new', 10):{},
                ('old', 11): {}
            }
        },
        ('Spanish', 4): {},
        ('French', 5):  {
            ('Grammar', 7): {}
        },
        ('Dutch', 8): {
            ('Grammar', 9): {
                ('new', 10):{}
            }
        }
    }
}


def _loop(topic, topics_dict):
    if (topic[0], topic[1]) in topics_dict.keys():
        return topics_dict[(topic[0], topic[1])]
    else:
        for k, v in topics_dict.items():
            if v != {}:
                if (result := _loop(topic, v)) is not None:
                    return result

topic = ('Grammar', 9)
trim_mydict = _loop(topic, mydict)
print(trim_mydict)

>>> {('new', 10): {}}
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