months = {"January": 31, "February": 28, "March": 31, "April": 30, "May": 31,
          "June": 30, "July": 31, "August": 31, "September": 30, "October": 31,
          "November": 30, "December": 31}

def mykey(t):
    """ Customize your sorting logic using this function.  The parameter to
    this function is a tuple.  Comment/uncomment the return statements to test
    different logics.
    """
    return t[1]              # sort by number of days in the month
    #return t[1], t[0]       # sort by number of days, then by month name
    #return len(t[0])        # sort by length of month name
    #return t[0][-1]         # sort by last character of month name


# Since a dictionary can't be sorted by value, what you can do is to convert
# it into a list of tuples with tuple length 2.
# You can then do custom sorts by passing your own function to sorted().
months_as_list = sorted(months.items(), key=mykey, reverse=False)

for month in months_as_list:
    print month

另一个答案中提到的集合解决方案绝对是极好的，因为您在键和值之间保留了一种联系，这在字典中是极其重要的。

我不同意另一个答案中的第一选择，因为它会扔掉钥匙。

我使用了上面提到的解决方案（代码如下所示），并保留了对键和值的访问权，在我的情况下，排序是对值进行的，但重要的是对值排序后的键排序。

from collections import Counter

x = {'hello':1, 'python':5, 'world':3}
c=Counter(x)
print( c.most_common() )


>> [('python', 5), ('world', 3), ('hello', 1)]

您可以使用collections.Counter。注意，这将适用于数值和非数值。

>>> x = {1: 2, 3: 4, 4:3, 2:1, 0:0}
>>> from collections import Counter
>>> #To sort in reverse order
>>> Counter(x).most_common()
[(3, 4), (4, 3), (1, 2), (2, 1), (0, 0)]
>>> #To sort in ascending order
>>> Counter(x).most_common()[::-1]
[(0, 0), (2, 1), (1, 2), (4, 3), (3, 4)]
>>> #To get a dictionary sorted by values
>>> from collections import OrderedDict
>>> OrderedDict(Counter(x).most_common()[::-1])
OrderedDict([(0, 0), (2, 1), (1, 2), (4, 3), (3, 4)])

您还可以使用可以传递给参数键的自定义函数。

def dict_val(x):
    return x[1]

x = {1: 2, 3: 4, 4: 3, 2: 1, 0: 0}
sorted_x = sorted(x.items(), key=dict_val)

我刚刚从Python for Everyone学习了相关技能。

您可以使用临时列表来帮助您对词典进行排序：

# Assume dictionary to be:
d = {'apple': 500.1, 'banana': 1500.2, 'orange': 1.0, 'pineapple': 789.0}

# Create a temporary list
tmp = []

# Iterate through the dictionary and append each tuple into the temporary list
for key, value in d.items():
    tmptuple = (value, key)
    tmp.append(tmptuple)

# Sort the list in ascending order
tmp = sorted(tmp)

print (tmp)

如果要按降序排序列表，只需将原始排序行更改为：

tmp = sorted(tmp, reverse=True)

使用列表理解，一行是：

# Assuming the dictionary looks like
d = {'apple': 500.1, 'banana': 1500.2, 'orange': 1.0, 'pineapple': 789.0}
# One-liner for sorting in ascending order
print (sorted([(v, k) for k, v in d.items()]))
# One-liner for sorting in descending order
print (sorted([(v, k) for k, v in d.items()], reverse=True))

样本输出：

# Ascending order
[(1.0, 'orange'), (500.1, 'apple'), (789.0, 'pineapple'), (1500.2, 'banana')]
# Descending order
[(1500.2, 'banana'), (789.0, 'pineapple'), (500.1, 'apple'), (1.0, 'orange')]

从Python 3.6开始，dict对象现在按插入顺序排序。这是Python 3.7规范中的正式版本。

>>> words = {"python": 2, "blah": 4, "alice": 3}
>>> dict(sorted(words.items(), key=lambda x: x[1]))
{'python': 2, 'alice': 3, 'blah': 4}

在此之前，您必须使用OrderedDict。

Python 3.7文档说明：

在3.7版中更改：字典顺序保证插入顺序该行为是CPython在3.6中的实现细节。