adding some code for stack and queue in python #771

nandiya · 2020-10-16T11:50:53Z

code example for queue and stack implementation in python

[x] following rule
[x] Only implement algorithms that are already in the AAA
[x] only one language and one algorithm
[x] already test my code

nandiya · 2020-10-16T11:54:32Z

@Amaras please review my code and can it be used?

Amaras

So, I have only done a code review. I don't even discuss the opportunity of adding code example on this chapter...
Don't worry if I'm a bit too harsh, I am usually on code, be it from myself or others.
Also, I don't have write access to the repository, so I couldn't officially approve your code, even if I wanted to

Amaras · 2020-10-16T12:58:08Z

contents/stacks_and_queues/code/python/stack_queue.py

+class Node:
+    def __init__(self, val):
+        self.value = val
+        self.next = None


Why do you want to recreate a linked list structure inside Python?

ahh, I thought this folder for basic implementation in python and we can contribute in any language, so that's why i tried to make one.
well in python itself already has list() which we can used simply, so yeah back to my first reason..

I'm still not sure this a good idea, but I'll let you use it

contents/stacks_and_queues/code/python/stack_queue.py

Amaras · 2020-10-16T13:01:52Z

contents/stacks_and_queues/code/python/stack_queue.py

+        else :
+            temp = Node(val)
+            temp.next = self.stack_list
+            self.stack_list = temp


The way you push to the stack seems weird... You push to the beginning, which is not usual. Why don't you simply use a list object instead of your linked list?

ahh this is back to the first reason.. i'm just implementing the basic way with python, and yeah I thought u're one of the reviewer, bcs I saw your name merged it, sorry abt that

I now have write access to the repo, so I can now merge if I want. Things change a lot in a year (sorry about the delay) 😄

contents/stacks_and_queues/code/python/stack_queue.py

Amaras · 2020-10-16T13:06:29Z

contents/stacks_and_queues/code/python/stack_queue.py

+    def pop(self):
+        if self.stack_list == None:
+            print ("Stack is Empty")
+            return None


You should probably just raise a ValueError exception instead of returning None, as the Node value can actually be None, and it doesn't help you programmatically differentiate between a None value, and an empty Stack

contents/stacks_and_queues/code/python/stack_queue.py

ntindle · 2021-08-28T04:53:48Z

[lang: python]

leios · 2021-09-15T16:50:11Z

What is the state of this PR? I think there are a few lingering changes to be made, but after that, we now have code for stacks and queues, so this can probably be merged in

henrikac · 2021-10-19T11:16:41Z

contents/stacks_and_queues/stacks_and_queues.md

@@ -15,6 +15,12 @@ The notation for this depends on the language you are using. Queues, for example

 ## License

+## Example Code
+{% method %}


I could be wrong but are stack and queue not split into two separate examples?

{% method %} # add stack example {% endmethod %} {% method %} # add queue example {% endblock %}

Yeah, we'll probably have to change that to fit the current published format indeed.

Amaras · 2021-10-21T20:49:17Z

I need to re-review this one for sure (wow, it's been a while). Doing that tomorrow or this weekend!

Amaras

OK, so I still have some problems with your code, but overall it's more an inconsistency.

I'd prefer the code to be more pythonic (mainly that would mean using the __str__ method instead of the print method, and removing the abbreviations) before merging, though, if you're still into that.

Amaras · 2021-10-22T22:57:05Z

contents/stacks_and_queues/code/python/stack_queue.py

+        else :
+            temp = Node(val)
+            temp.next = self.stack_list
+            self.stack_list = temp


I now have write access to the repo, so I can now merge if I want. Things change a lot in a year (sorry about the delay) 😄

Amaras · 2021-10-22T22:58:09Z

contents/stacks_and_queues/code/python/stack_queue.py

+example_stack.push(2)
+example_stack.push(3)
+example_stack.print()
+print("you just pop ", example_stack.pop())


Suggested change

print("you just pop ", example_stack.pop())

print("you just popped", example_stack.pop())

Amaras · 2021-10-22T23:05:15Z

contents/stacks_and_queues/code/python/stack_queue.py

+    def print(self):
+        temp = self.queue_list
+        while temp.next:
+            print(temp.value)
+            temp = temp.next
+        print(temp.value)


You might want to do the same as with the Stack.print method, and say what you are printing.

A better (I think) way to implement the printing would be to provide a __str__ method, and let Python handle the printing when doing print(example_stack) and print(example_queue)

Amaras · 2021-10-22T23:06:33Z

contents/stacks_and_queues/stacks_and_queues.md

@@ -15,6 +15,12 @@ The notation for this depends on the language you are using. Queues, for example

 ## License

+## Example Code
+{% method %}


Yeah, we'll probably have to change that to fit the current published format indeed.

Amaras · 2021-10-22T23:07:27Z

contents/stacks_and_queues/code/python/stack_queue.py

+class Node:
+    def __init__(self, val):
+        self.value = val
+        self.next = None


I'm still not sure this a good idea, but I'll let you use it

henrikac

It looks like you have switched stack and queue around. Your stack adds and removes items to/from the beginning of the stack, and your queue to the end. This is, to my understanding, usually the other way around and the other language implementations also does it this way.

henrikac · 2021-10-23T19:24:29Z

contents/stacks_and_queues/code/python/stack_queue.py

+            self.stack_list = self.stack_list.next
+            return pop_val
+
+    def get_top(self):


Minor thing: maybe drop get_ and just call it top - same with get_front -> front?

FVFYK3GEHV22 added 2 commits October 16, 2020 18:48

adding some code for stack and queue in python

212ed99

delete unneeded import

8d2852d

Amaras requested changes Oct 16, 2020

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FVFYK3GEHV22 added 2 commits October 16, 2020 20:40

changing some identyty comparison and raise error

60ae9d8

deleting some comparison

4b4a64c

berquist added the Implementation This provides an implementation for an algorithm. (Code and maybe md files are edited.) label Oct 16, 2020

berquist added hacktoberfest-accepted Hacktoberfest The label for all Hacktoberfest related things! labels Oct 27, 2020

leios mentioned this pull request Nov 5, 2020

feat(ts): stack and queue implementation #775

Merged

github-actions bot added the lang: python Python programming language label Aug 28, 2021

henrikac reviewed Oct 19, 2021

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Amaras requested changes Oct 22, 2021

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henrikac reviewed Oct 23, 2021

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Michae1CC mentioned this pull request Mar 30, 2023

Added a stack and queue implementation for python3 #1008

Merged

leios closed this Mar 30, 2023

	print("you just pop ", example_stack.pop())
	print("you just popped", example_stack.pop())

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adding some code for stack and queue in python #771

adding some code for stack and queue in python #771

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nandiya commented Oct 16, 2020

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ntindle commented Aug 28, 2021

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Amaras commented Oct 21, 2021

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