Python: DFS Depth First Search

Learn to code the DFS depth first search graph traversal algorithm in Python. I recommend you watch my DFS overview video first.

ALGORITHMS

[cmhg]

That intro makes me feel like i have to run

[bashierdahman]

I love this! Thank you for going thru each line of code, absolute best video I've ever seen

[theophileavoyne]

Thank you this is great!

I think lines 29-33's iteration unnecessarily increase the complexity.
I would replace it by a simple :

[Qizot]

great example of dfs, understandable code and great explanation, I was looking for it for ages :)

[mr_phamtastic]

Thank you for this good concise explanation of code

[priscillaroy]

Thank you so much Joe. This really helped me a lot in understanding

[ninano]

Great!!! Could make video about Hamiltonian cycles (directed/undirected graphs). It would be awesome)

[wilsonlwtan]

Don't really understand the purpose of the global time variable. I thought the color of the vertices should be sufficient to say it has been visited? So why do we need the time?

[ftakelait]

Thanks a lot for the video. How about the case when we have a directed graph, please?

[priyankvenkatesh]

Hello, how would you add a node counter to an already existing code.

[anujtipparaju]

hey Joe!, so the add_neighbors is a Vertex class method, and how are you using it in the Graph class(in the add_edge method)
without any Vertex.method() ?

[lukeelliott]

This is helping me a ton. I am wondering why the graph class did not need the customary "__init__" function that I am so used to seeing.

[ashutoshnegi]

Why is there a BOSS MUSIC at the start of the video

[oggiai]

The code is available on my github site, and you can see the part-1 DFS video here, I recommend watching that video before this one.

[giampy]

The explanations are amazing but the initial and final soundtrack is a torture to my ears

[AhmedAdel-qldt]

I have an error with this line of code
def print_graph(self):
for key in
print(key + + " " +
can anyone solve it?

[ouafaebouamar]

hi! sorry for the stupid question, but does this code work for all types of examples of DFS?
ps: i have an exam on the 7th. please help

[ippikineko]

line 40 is off the page, anyone know what it says or where to find the code? thanks

[thegrowers]

Hi, aspiring python dev here, often times when doing any graph search algorithm, do you normally have to build the graph and then build out your DFS as well? Or would you normally get a preconstructed graph?

[darkcaper]

What's the reason for using set in the addneighbours() definition? Shouldn''t the neighbours list not have any duplicates in the first place?