Added reverse_linked_list.py #4973

immiel · 2021-10-04T03:33:12Z

I looked around and noticed that there's no algorithm that reverse a linked list and returns them. The closest I could find prints them instead of returning them as a function. And so, here it is.

The function only have one input and one output. The function works as follows; it pops data from the beginning of input and append them to the beginning of output, and this is performed until there's no more node in input.

For tests, I added doctests for short and concise explanation as to how to use the function, and additional tests if the code is run independently. Hopefully, this piece of code and its documentation could be a suggestion for someone that needs to know how to reverse a linked list.

Describe your change:

Add an algorithm?
Fix a bug or typo in an existing algorithm?
Documentation change?

Checklist:

I looked around and noticed that there's no algorithm that reverse a linked list and returns them. The closest I could find prints them instead of returning them as a function. And so, here it is. The function only have one input and one output. The function works as follows; it pops data from the beginning of input and append them to the beginning of output. For tests, I added doctests for short and concise explanation as to how to use the function, and additional tests if the code is run independently. Hopefully, this piece of code and its documentation could be a suggestion for someone that needs to know how to reverse a linked list.

ghost

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ghost · 2021-10-04T03:33:16Z

data_structures/linked_list/reverse_linked_list.py

+        self.item = item
+        self.next = next
+
+    def __repr__(self) -> str:


As there is no test file in this pull request nor any test function or class in the file data_structures/linked_list/reverse_linked_list.py, please provide doctest for the function __repr__

poyea · 2021-10-04T03:44:04Z

Actually there's one: https://github.com/TheAlgorithms/Python/blob/master/data_structures/linked_list/singly_linked_list.py#L146. However, you can always improve the current version by adding tests (nice test cases that you have) and type hints.

poyea · 2021-10-04T03:44:48Z

So you can close this and open a new one, or update the current singly_linked_list.py in this PR. I think both would work.

immiel · 2021-10-04T03:46:20Z

So you can close this and open a new one, or update the current singly_linked_list.py in this PR. I think both would work.

Alright. I guess I'll close this one and open a new one to update that one. Thank you for the help!

This is a followup to TheAlgorithms#4973 (comment) As per given suggestion, I've added type hints to certain methods that don't have them. I have also added documentation and example doctests as a usage example for (most of) those that don't have them. I have also added another test case following the previous test case's format. I noticed that the existing test case from previous pull request might be redundant with the ones I've made, so I decided to create a specific situation where the linked list would have to keep different kinds of data types for each node, in `test_singly_linked_list_2` test function.

This is a followup to TheAlgorithms#4973 (comment) As per given suggestion, I've added type hints to certain methods that don't have them. I have also added documentation and example doctests as a usage example for (most of) those that don't have them. I have also added another test case following the previous test case's format. I noticed that the existing test case from previous pull request might be redundant with the ones I've made, so I decided to create a specific situation where the linked list would have to keep different kinds of data types for each node, in `test_singly_linked_list_2` test function. Some minor changes in strings has been done to keep things consistent with other parts of the document. If it is undesirable, please let me know.

…st cases (#4988) This is a followup to #4973 (comment) As per given suggestion, I've added type hints to certain methods that don't have them. I have also added documentation and example doctests as a usage example for (most of) those that don't have them. I have also added another test case following the previous test case's format. I noticed that the existing test case from previous pull request might be redundant with the ones I've made, so I decided to create a specific situation where the linked list would have to keep different kinds of data types for each node, in `test_singly_linked_list_2` test function. Some minor changes in strings has been done to keep things consistent with other parts of the document. If it is undesirable, please let me know.

…st cases (TheAlgorithms#4988) This is a followup to TheAlgorithms#4973 (comment) As per given suggestion, I've added type hints to certain methods that don't have them. I have also added documentation and example doctests as a usage example for (most of) those that don't have them. I have also added another test case following the previous test case's format. I noticed that the existing test case from previous pull request might be redundant with the ones I've made, so I decided to create a specific situation where the linked list would have to keep different kinds of data types for each node, in `test_singly_linked_list_2` test function. Some minor changes in strings has been done to keep things consistent with other parts of the document. If it is undesirable, please let me know.

ghost added awaiting reviews This PR is ready to be reviewed require tests Tests [doctest/unittest/pytest] are required labels Oct 4, 2021

ghost reviewed Oct 4, 2021

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Added doctest to __repr__

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ghost removed the require tests Tests [doctest/unittest/pytest] are required label Oct 4, 2021

poyea self-assigned this Oct 4, 2021

immiel closed this Oct 4, 2021

immiel mentioned this pull request Oct 4, 2021

singly_linked_list.py: Added additional documentation, type hints and test cases #4988

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immiel deleted the patch-4 branch October 20, 2021 09:59

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Added reverse_linked_list.py #4973

Added reverse_linked_list.py #4973

immiel commented Oct 4, 2021

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immiel commented Oct 4, 2021

Added reverse_linked_list.py #4973

Added reverse_linked_list.py #4973

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immiel commented Oct 4, 2021

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