二叉搜索树频率计数器

Question

我需要读取一个文本文件，去掉不必要的标点符号，将单词小写，并使用二叉​​搜索树函数来制作一个由文件中的单词组成的单词二叉搜索树。

我们被要求计算重复单词的频率，并询问总字数和总唯一字数。

到目前为止，我已经解决了标点符号，文件读取完成，小写完成，二叉搜索树基本完成，我只需要弄清楚如何在代码中实现“频率”计数器。

我的代码如下：

class BSearchTree :
class _Node :
    def __init__(self, word, left = None, right = None) :
        self._word = word
        self._count = 0
        self._left = left
        self._right = right

def __init__(self) :
    self._root = None
    self._wordc = 0
    self._each = 0

def isEmpty(self) :
    return self._root == None


def search(self, word) :
    probe = self._root
    while (probe != None) :
        if word == probe._word :
            return probe
        if word < probe._value :
            probe = probe._left
        else : 
            probe = probe._right
    return None     

def insert(self, word) :
    if self.isEmpty() :
        self._root = self._Node(word)
        self._root._freq += 1 <- is this correct?
        return

    parent = None               #to keep track of parent
                                #we need above information to adjust 
                                #link of parent of new node later

    probe = self._root
    while (probe != None) :
        if word < probe._word :     # go to left tree
            parent = probe          # before we go to child, save parent
            probe = probe._left
        elif word > probe._word :   # go to right tree
            parent = probe          # before we go to child, save parent
            probe = probe._right

    if (word < parent._word) :      #new value will be new left child
        parent._left = self._Node(word)
    else :    #new value will be new right child
        parent._right = self._Node(word)

因为格式化要了我的命，这是它的后半部分。

class NotPresent(Exception) :
pass

def main():
t=BST()

file = open("sample.txt")           
line = file.readline()                      
file.close()                            


#for word in line:
#   t.insert(word)
# Line above crashes program because there are too many 
# words to add. Lines on bottom tests BST class
t.insert('all')
t.insert('high')
t.insert('fly')
t.insert('can')
t.insert('boars')
#t.insert('all') <- how do i handle duplicates by making 
t.inOrder()        #extras add to the nodes frequency?

感谢您的帮助/试图提供帮助！

Answer 1

首先，最好将Node 的_freq 初始化为1，而不是在BST 的insert() 中进行初始化

（还有1个：在python编码约定中，不建议在写入默认参数值时使用空格。）

    def __init__(self, word, left=None, right=None) :
        self._word = word
        self._freq = 1
        self._left = left
        self._right = right

只需添加最后 3 行：

    probe = self._root
    while (probe != None) :
        if word < probe._word :     # go to left tree
            parent = probe          # before we go to child, save parent
            probe = probe._left
        elif word > probe._word :   # go to right tree
            parent = probe          # before we go to child, save parent
            probe = probe._right
        else:
            probe._freq += 1
            return