按值对Python字典排序-这里有什么问题？

考虑以下Python代码：

with open('data.json', 'rb') as fp:
data = json.load(fp,encoding="utf-8")

list_of_years = []

for datas in data:
list_of_years.append(data[datas]['year'])

print set(list_of_years)

received_letters = {}

sent_letters = {}

for years in set(list_of_years):
print years
number_of_sent_letters =0
number_of_received_letters =0
for datas in data:
    if (data[datas]['year'] == years):
        if ' Luther, Martin' in data [datas] ['sender']:
            number_of_sent_letters+=1
print "The number of sent letters:" +str(number_of_sent_letters)
sent_letters[years]=number_of_sent_letters

for datas in data:
    if (data[datas]['year'] == years):
        if ' Luther, Martin' in data [datas] ['receiver']:
            number_of_received_letters+=1
print "The number of received letters:" +str(number_of_received_letters)
received_letters[years]=number_of_received_letters

sent_letters[years] = {number_of_sent_letters}
sorted_sent_letters[years] = sorted(sent_letters[years].iteritems(), key=operator.itemgetter(1))

received_letters[years] = {number_of_received_letters}
sorted_received_letters[years] = sorted(received_letters[years].iteritems(), key=operator.itemgetter(1))

我试图按照另一个关于按值对字典排序的问题的答案中的建议，对两个字典进行排序，分别是

收到的字母

和

发出的字母

。。。我得到的结果就是错误消息

set对象没有属性iteritems

关于最后一行的第四行

---

这里怎么了？

首先，您说您正在尝试对字典进行排序，但您的代码只尝试对包含单个项的集合进行排序

sent_letters[years] = {number_of_sent_letters}
sorted_sent_letters[years] = sorted(sent_letters[years].iteritems(), key=operator.itemgetter(1))

由于

number\u-of-sent\u-letters

是一个整数，

sent\u-letters[years]

只是一个单例集合

我想你想做：

sorted_sent_letters = sorted(sent_letters.iteritems(), key=operator.itemgetter(1))

---

你应该在循环之外做…

我很确定你想要的是这个，但我不清楚你想要做什么，因为你在最后生成的是两本字典，每年都与字母数量有关

with open('dataset.json', 'rb') as fp:
    dataset = json.load(fp, encoding="utf-8")

set_of_years = {}

for data in dataset:
    set_of_years.append(data['year'])

print set_of_years

sent_letters, received_letters = {}, {}

for year in set_of_years:

    print year

    for data in dataset:
        if (data['year'] == year):
            if 'Luther, Martin' in data['sender']:
                sent_letters[year]     += 1
            if 'Luther, Martin' in data['receiver']:
                received_letters[year] += 1

    print "The number of sent letters: %d" % sent_letters[year]
    print "The number of received letters: %d" % received_letters[year]

之后，这取决于你想要什么。您已将看起来像排序的内容编码为一个（日期，计数）元组列表，并按第二个值（计数）对其进行排序。如果写得好的话

itemgetter_1 = operator.itemgetter(1)
sorted_sent_letters     = sorted(sent_letters.items(),     key=itemgetter_1)
sorted_received_letters = sorted(received_letters.items(), key=itemgetter_1)

或者，使用lambdas

count_key = lambda pair: pair[1]
sorted_sent_letters     = sorted(sent_letters.items(),     key=count_key)
sorted_received_letters = sorted(received_letters.items(), key=count_key)

但似乎更可能的情况是，您只需要一份按字母计数排序的年份列表，因此您需要

count_key = lambda year: data[year]
sorted_sent_letters     = sorted(sent_letters,     key=count_key)
sorted_received_letters = sorted(received_letters, key=count_key)

---

我希望这能有所帮助

从表面上看，你的压痕是错误的。例如，第二行

data=json.load（fp，encoding=“utf-8”）

应该以空格开头，这样程序就不会编译。如果你有一个正确缩进的版本，那么请发布它，因为我们不能告诉你的意思比编译器更好！我还确信

data[datas]['year']

应该是

datas['year']

，这可能是您问题的根源。您从

打印集（年列表）

获得了什么输出？请修复代码缩进并提供错误的完整追溯。