打印按值排序的字典 [英] Print a dict sorted by values

问题描述

我基本上是在尝试遍历字典，然后将键/值从最大值打印到最小值.我一直在搜索此网站，很多人都在使用lambda，但我不确定它的工作方式，因此暂时不尝试使用它.

I'm basically trying to iterate through a dict and print out the key / values from largest value to lowest. I have been searching this site and a lot of people are using lambda but I'm not really sure how its working so I'm trying to avoid it for now.

dictIterator = iter(sorted(bigramDict.iteritems()))
for ngram, value in dictIterator:
    print("There are " + str(value) + " " + ngram)

查看上面的代码，我认为它将创建一个迭代器，该迭代器按从最大到最小的顺序返回键/值对，但不是.

Looking over the code above I assumed it would make an iterator which returns the key/value pairs in order from largest to smallest but it's not.

任何人都可以看到问题所在吗?或执行此操作的另一种方法?

Can anyone see what the problem is? or another method of doing this?

推荐答案

通过将第一个元素比第二个元素更重要，一个人可以利用对元组进行排序的事实:

One can take advantage of the fact that sort works on tuples by considering the first element as more important than the second etc:

d = { "a":4, "c":3, "b":12 }
d_view = [ (v,k) for k,v in d.iteritems() ]
d_view.sort(reverse=True) # natively sort tuples by first element
for v,k in d_view:
    print "%s: %d" % (k,v)

输出:

b: 12
a: 4
c: 3

单行生成器表达式:

sorted( ((v,k) for k,v in d.iteritems()), reverse=True)

输出:

[(12, 'b'), (4, 'a'), (3, 'c')]

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