DEPTH FIRST SEARCH WITH PYTHON

In this video we'll be learning about trees, traversal, depth-first search (DFS) and how we can implement DFS easily using both recursion and iteration.

Bonus! Using a stack and Python to find unbalanced parenthesis

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[howCode]

I'll add a new article to howcode.org tomorrow with some extra stuff I didn't have time to talk about in the video, it's a bit late for me at the moment! 🕑

[EmceeEdits]

actually the best explaintion ive seen after hours of searching for explanations - very informative and easy to follow

[JTNewby]

Dude, I can't get over how easy it is to print the different orders by just moving the print statement. Thank you!

[ploterman]

I have been looking for a easy to follow video on this for some time and finally I have found one. Thank you and keep up the good work!

[hawundlovu]

Great video man! I really feel you made everything less complicated!

[hezo]

Glad you have posted again Francis <3

[thenidoking]

Thank you for this! Best and simplest ive seen yet.

[dereksparks]

Cleanest explanation I've found. Well done!

[amjadattar]

class Node:
def __init__(self, value, left = None, right=None):
self.value= value
self.left = left
self.right = right
def __str__(self):
return "Node("+str(self.value)+")"

def walk(tree):
if tree is not None:
print(tree)
walk(tree.left)
walk(tree.right)

def walk2(tree, stack):
stack.append(tree)
while len(stack) > 0:
node = stack.pop()
if node is not None:
print(node)
stack.append(node.right)
stack.append(node.left)

mytree = Node('A', Node('B', Node('D'), Node('E')), Node('C', Node('F'), Node('G')))

walk(mytree)

[mariagu]

Thank you! Very easy to understand for me!

[sweetphilly]

May be worth adding/mentioning a search term to your functions since these are searching algorithms. It may be obvious for some to just add an if-statement and return some value (i.e. boolean, Node), but definitely not all will know. Great video nonetheless!

[NoName-kxfs]

Man, do more, someday I will learn English enough to watch all your videos !!! I will learn English for you and your fucking great content in the world. <3

[AbhishekKumar-ytmz]

Please do python graphs and other data structures as well as algorithms

[codingwithmiles]

I tried creating an empty list and pass it in the walk2 function but I got this error

TypeError: 'builtin_function_or_method' object is not subscriptable

any help?

my code
#the Stack
stack = []

#calling walk2 function
print("THE ITERATIVE WAY")
walk2(mytree, stack)

[rithannandakumar]

No proper explanation of creating the nodes

[misterwhopper]

Depth first search? Nah, I prefer bread search first

I'm so tired