检查二进制树python中的现有值

Question

Have some errors and been stuck on this problem for awhile. I read words from a file like this below but the problem is with the if statements. it doesn't print an existing value it just keeps printing all values to the screen. I am using python 3.3.. If you check the file the only value it would print is via and not add it again to the tree.

Textfile - words.txt

nia
ria
via
sia
via

Code

class Bintree:
    def __init__(self, data):
        self.left = None 
        self.right = None 
        self.data = data 

    def put(self, data):
        if data < self.data:
            if self.left is None:
                self.left = Bintree(data)
            else:
                self.left.put(data)
        else:
            if self.right is None:
                self.right = Bintree(data)
            else:
                self.right.put(data)

    def write(self):  
        if self.left: 
            self.left.write()
        print(self.data) 
        if self.right: 
            self.right.write()

    def exists(self, data):
        if data < self.data:
            if self.left is None:
                return None, None
            return self.left.exists(data, self)
        elif data > self.data:
            if self.right is None:
                return None, None
            return self.right.exists(data, self)
        else:
            return self.data


root = Bintree("root")
with open("words.txt", "r", encoding = "utf-8") as file:
    for row in file:
        word = row.strip()
        checklist = root.exists(word)
        if checklist == word:
            print(word, end = " ")
        else:
            root.put(word)
print("\n")

Answer 1

I would remove the "self" keyword in the invocation of the exists method. When calling a method we do not have to specify the "self" keyword.

So, instead of:

return self.left.exists(data, self)
return self.right.exists(data, self)

I would simply use:

return self.left.exists(data)
return self.right.exists(data)

When passing self to the method, you should actually get a traceback complaining that you are passing an extra argument to exists() method. I quickly tried running your code and got a traceback like this:

Traceback (most recent call last):
  File "t.py", line 44, in <module>
    checklist = root.exists(word)
  File "t.py", line 30, in exists
    return self.left.exists(data, self)
TypeError: exists() takes exactly 2 arguments (3 given)

Answer 2

How about this:

....
with open("words.txt","r",encoding="utf-8") as file:
    a=file.readlines() # this reads the entire file as a list. Each line is an item in the list.
    b=[i.strip('\n') for i in a] # this will get rid of newline characters '\n' in each item of the list
    m=max([b.count(i) for i in b]) # this line will get you the highest number of occurrences of a word in your list
    c=set([i for i in b if b.count(i)==1]) # this line will give you all words that occur m times
    print(c)