Question

我有以下Dict：

{'children': [{'children': [{'criteria': ['United Kingdom'],
     'name': ['3'],
     'prediction': ['0.256'],
     'weights': ['604']},
    {'criteria': ['United States'],
     'name': ['4'],
     'prediction': ['0.231'],
     'weights': ['5316']}],
   'criteria': ['United Kingdom United States'],
   'name': ['2'],
   'prediction': ['0.233'],
   'variableNames': ['Country name'],
   'weights': ['5920']},
  {'children': [{'criteria': [' Brazil Canada'],
     'name': ['6'],
     'prediction': ['0.153'],
     'weights': ['10029']},
    {'criteria': ['France Germany Spain Turkey'],
     'name': ['7'],
     'prediction': ['0.053'],
     'weights': ['1335']}],
   'criteria': [' Brazil Canada France Germany Spain Turkey'],
   'name': ['5'],
   'prediction': ['0.141'],
   'variableNames': ['Country name'],
   'weights': ['11364']}],
 'criteria': ['l 1'],
 'name': ['1'],
 'prediction': ['0.173'],
 'variableNames': ['Country name'],
 'weights': ['17284']}

我需要找到max＆amp;两个预测的最小值和权重，它们都是字符类型，因此需要将它们转换为Float / int，然后在迭代所有键/值时找到它们的最大/最小值。

使用一些previs很好的问题，我发现如果这些值可能有效：

 max(test, key=lambda x: test[x]['prediction'])
Traceback (most recent call last):

  File "<ipython-input-43-e7d4b2e19f21>", line 1, in <module>
    max(test, key=lambda x: test[x]['prediction'])

  File "<ipython-input-43-e7d4b2e19f21>", line 1, in <lambda>
    max(test, key=lambda x: test[x]['prediction'])

TypeError: list indices must be integers, not str

这就像我将值转换为int / float：

一样接近

for body in test:
     test[body]['prediction'] = float(test[body]['prediction'])
     test[body]['weights'] = int(test[body]['weights'])

再次引发类似的错误。

Answer 1

你需要一个递归函数来遍历你的词典

def maxr(D, k):
    return max([float(D[k][0])] + [maxr(i, k) for i in D.get('children', [])])

输出

>>> maxr(D, 'prediction')
0.256

您可以类似地定义函数minr

Answer 2

如果您想要的只是特定字段的最大值，那么John的解决方案可以正常工作，但我认为拥有一个递归生成每个字典的生成器会更灵活。

def iter_children(data):
    yield data
    for child in data.get('children', []):
        for c in iter_children(child):  # if you're using Python3 "yield from" can simplify this
            yield c


print max(float(c['prediction'][0]) for c in iter_children(raw_data))
print max(int(c['weights'][0]) for c in iter_children(raw_data))

然后，只有在＆＃34;巴西＆＃34;之后才能轻松做到最好的预测。符合标准。

print max(float(c['prediction'][0]) for c in iter_children(raw_data) if 'Brazil' in c['criteria'][0])

在Python中使用字符值查找嵌套Dict的最大值

2 个答案: