我正在努力从树叶上造一棵哈夫曼树。我有我的分类名单，但不知道如何继续

Question

所以这个函数需要一个字符串，我用下面的代码让它创建一个元组列表[character，frequency]。我们没有使用可预测性，只是实际频率。有什么建议可以让我开始构建正确的树，使我可以向下遍历它来添加它的1和0？在

from operator import itemgetter, attrgetter, methodcaller
def code(msg):
# list of characters already counted
characters = []
# list of tuples
frequencies = []
# look through the message
for char in msg:
    if char not in characters:
        print(char)

        characters.append(char)
        thisCount = 0
        # if current character has already been added to list
        for chara in msg:
            if char == chara:
                # increase its count if another found
                thisCount = thisCount + 1
        # create its tuple
        tup = (char, thisCount)
        # add tuple to frequencies
        frequencies.append(tup)

# sort tuple list by element[1] numerically
sortedFreq = sorted(frequencies, key=lambda x: x[1])
print(sortedFreq)
make_Tree(sortedFreq)
return

Answer 1

首先，熟悉处理这个应用程序的Python结构。一个基本字典可以比你的数组对做得更好，而计数器可以很快做到这一点：

from collections import Counter
freq = Counter(msg)

freq现在是一个字典的形式

^{pr2}$

代表“你好”的信息。现在，要获得元组的排序列表，只需从计数器获取元组并将其插入排序：

sortedFreq = sorted(freq.items(), key=lambda x: x[1])

---

现在开始施工。我不知道你设置了什么数据结构，但算法基本上是这样的：

while len(sortedFreq) > 1
    join the last two elements
    re-sort the tree

这能让你找到解决方案吗？在