Answer 1

I think your code should look more like this:

def inorder(self, file):    
    if self._left is not None:
        file.write(str(self) + ' ')
        self._left.inorder(file)
    file.write(str(self) + ' ')
    if self._right is not None:
        file.write(str(self) + ' ')
        self._right.inorder(file)

Note that:

1. The file to write to is an argument, passed to the recursive calls, not opened each time;
2. Testing for None by identity not equality; and
3. I am assuming that you have a tree structure where self._left and self._right are instances of the same class as self (as you've provided so little of the class, it's hard to be sure, but self.inorder(self._left) makes no sense).

When you call this, on some instance instance of your class, it would look like:

with open(...) as f:
    instance.inorder(f)

Answered by: Patrick310 | Posted: 07-01-2022

Similar questions

arrays - Can parallel traversals be done in MATLAB just as in Python?

Using the zip function, Python allows for loops to traverse multiple sequences in parallel. for (x,y) in zip(List1, List2): Does MATLAB have an equivalent syntax? If not, what is the best way to iterate over two parallel arrays at the same time using MATLAB?

---

python - Recursion - how do you extract from specific traversals

Lets say you have a string: abcde And a set of strings: ab, cde, abcd, a, bcd, cd You want to find all possible concatenations from the set that form the string. You can use recursion to traverse through all possible concatenations from the set, but how would you return only those that satisfy the solution? The possible combinations: ab - cde - yes ab - cd - no abcd - no a ...

---

recursion - Traverse tree and return a node instance after n traversals in python

The end goal is to copy a node from one tree to another tree. I want to visit each node in a binary tree and return a node instance after a number of traverses. I cannot seem to figure out how to return a specific node. Every time the node returned matches the id of the root node since I pass the root node to the function. class node(): def __init__(self): self.parent = None self.left =...

---

algorithm - Tree Traversals, recursion is faster than iteration in python?

I have implement tree preorder traversal in python, but found that my recursive version is faster than iteration version. code is as below: from __future__ import print_function import time class Tree(): def __init__(self, value): self.value = value self.left = None self.right = None def build_tree(string): nodes = [0] + [Tree(s) for s in string] for i in range...

---

python - Can a directed graph have two DFS traversals?

Here is my DFS traversal algorithm (Recursive approach): def dfs(v,visited) : for i in Graph[v] : if i not in visited : visited.append(i) print(i) dfs(i,visited) n = int(input()) Graph = {} for i in range(n) : name= input(print("Enter ",i+1," vertex name")) list...

---

python - Traversals of Binary Trees

I am trying to implement in-order, pre-order, and post-order traversals of a binary tree. My implementation seems to work for trees with a small number of nodes (as I have checked by hand) but the online software I am using says there are cases that my implementation fails (it does not provide the input that causes my implementation to fail). I have looked through several other threads on this site but cannot seem to find ...

---

Still can't find your answer? Check out these communities...

PySlackers | Full Stack Python | NHS Python | Pythonist Cafe | Hacker Earth | Discord Python