访问嵌套字典列表中的值

Question

我的字典看起来像这样：

docScores = {0:[{u'word':2.3},{u'the':8.7},{u'if':4.1},{u'Car':1.7}],
             1:[{u'friend':1.2},{u'a':5.2},{u'you':3.8},{u'person':0.8}],
             ...
             29:[{u'yard':1.5},{u'gardening':2.8},{u'paint':3.7},{u'brush':1.6}]
            }

我想对每个列表的每个内部dict的值求和并将其存储在一个新的dict中，新的dict的键值为{0:2.3+8.7+4.1+1.7, 1:1.2+5.2+3.8+0.8, ... etc}即

for x in docScores[0]: #{0:
    for x in docScores[0][0].values(): #{,2.3}.
        sum = sum+x #where sum = 0 before loop
        docSum[0] = sum
    repeat this loop for every document

我尝试过的任何变化都会给我带来意想不到的输出。 谁能给我正确的语法吗？

Answer 1

此dict理解有效：

docScores = {0:[{u'word':2.3},{u'the':8.7},{u'if':4.1},{u'Car':1.7}],
             1:[{u'friend':1.2},{u'a':5.2},{u'you':3.8},{u'person':0.8}],
             29:[{u'yard':1.5},{u'gardening':2.8},{u'paint':3.7},{u'brush':1.6}]
            }

sum_d={k:sum(d.values()[0] for d in v) for k,v in docScores.items()}

print sum_d

打印：

{0: 16.8, 1: 11.0, 29: 9.6}

但是，更改数据结构可能更容易。 您可以有一个命令：

>>> NdocScores = {0:{u'word':2.3,u'the':8.7,u'if':4.1,u'Car':1.7},
...              1:{u'friend':1.2,u'a':5.2,u'you':3.8,u'person':0.8},
...              29:{u'yard':1.5,u'gardening':2.8,u'paint':3.7,u'brush':1.6}
...             }   

允许直接访问每个文档数据：

>>> NdocScores[0]
{u'Car': 1.7, u'the': 8.7, u'word': 2.3, u'if': 4.1}
>>> NdocScores[0][u'Car']
1.7
>>> sum(NdocScores[1].values())
11.0

>>> NdocScores[29]
{u'gardening': 2.8, u'yard': 1.5, u'brush': 1.6, u'paint': 3.7}

或者，仅具有字典列表，列表中的位置与doc索引相对应：

>>> lofdicts=[v for k,v in NdocScores.items()]
>>> lofdicts
[{u'Car': 1.7, u'the': 8.7, u'word': 2.3, u'if': 4.1}, {u'a': 5.2, u'person': 0.8, u'you': 3.8, u'friend': 1.2}, {u'gardening': 2.8, u'yard': 1.5, u'brush': 1.6, u'paint': 3.7}]
>>> lofdicts[0]
{u'Car': 1.7, u'the': 8.7, u'word': 2.3, u'if': 4.1}
>>> sum(lofdicts[1].values())
11.0

Answer 2

new_dict={}

docScores = {0:[{u'word':2.3},{u'the':8.7},{u'if':4.1},{u'Car':1.7}],
             1:[{u'friend':1.2},{u'a':5.2},{u'you':3.8},{u'person':0.8}],
             29:[{u'yard':1.5},{u'gardening':2.8},{u'paint':3.7},{u'brush':1.6}]
            }

for k,v in docScores.items():
    new_dict[k]=sum( sum(d.values()) for d in v )

print (new_dict) #{0: 16.8, 1: 11.0, 29: 9.6}

正如其他人提到的那样，您可以将其变成字典理解（python 2.7+）：

new_dict = {k : sum( sum(d.values()) for d in v ) for k,v in docScores.items() }

但是在这一点上，我认为理解变得非常难以理解（因此我不会这样做）。

另外，可能有人应该指出，如果您所有的字典键都是从0到29的连续整数，则您可能不应该使用字典来存储此数据-也许列表会更合适...

编辑

使用列表：

new_list = [sum( sum(d.values()) for d in v ) for _,v in sorted(docScores.items()) ]

Answer 3

>>> doc_scores = {
        0: [{u'word': 2.3}, {u'the': 8.7}, {u'if': 4.1}, {u'Car': 1.7}],
        1: [{u'friend': 1.2}, {u'a': 5.2}, {u'you': 3.8}, {u'person': 0.8}],
        29: [{u'yard': 1.5}, {u'gardening': 2.8}, {u'paint': 3.7}, {u'brush': 1.6}]
}
>>> dict((k, sum(n for d in v for n in d.itervalues())) 
         for k, v in doc_scores.iteritems())
{0: 16.8, 1: 11.0, 29: 9.6}

如果列表中的每个字典中只有一个值，则可以缩短此值：

>>> dict((k, sum(d.values()[0] for d in v)) for k, v in doc_scores.iteritems())
{0: 16.8, 1: 11.0, 29: 9.6}

Answer 4

和更多的oneline解决）

sum(reduce(lambda x, y: x+y, [d.values() for d in v for _,v in docScores.iteritems()]))

Answer 5

docScores = {0:[{u'word':2.3},{u'the':8.7},{u'if':4.1},{u'Car':1.7}],
             1:[{u'friend':1.2},{u'a':5.2},{u'you':3.8},{u'person':0.8}],
             2:[{u'yard':1.5},{u'gardening':2.8},{u'paint':3.7},{u'brush':1.6}]
            }


result = dict(enumerate(sum (sum(word.values()) for word in  word_list[1]) for word_list in sorted(docScores.items())  ) )