Create selectionsort.py #2
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Added selection sort algorithm code to data structure
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| # Here we use dictionary data structure to store our count of values mapped to respective names in the above photos | |||
| singers={"Selena Gomez": 112, "Taylor Swift": 178,"Ed Sheeran": 230,"Justin Bieber": 90,"John Legend": 190,"Beyoncé": 80} | |||
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please write global variable in
if name == 'main':
you can check in Jan's Binary Tree code.
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Will do and I searched for why is it necessary to add this, but nothing could clearly show me the reason. Could you please tell me why we should include this in ,sis?
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I updated if name == 'main':, but I wonder if the place I put in is correct
| singers={"Selena Gomez": 112, "Taylor Swift": 178,"Ed Sheeran": 230,"Justin Bieber": 90,"John Legend": 190,"Beyoncé": 80} | ||
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| # We then convert dictionary to list of only count values and in singers_list, it will be like this[112,178,230,90,190,80] | ||
| singers_list=list(singers.values()) |
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Oh so, it's needed to add if name == 'main': two times?
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| # Starting from here, we define a function for selection sort | ||
| def selectionSort(singers_list): | ||
| #This is an empty list which will later be filled with sorted counting values |
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write docstring instead of comments
Please check Jan's code.
docstring should follow this format
'''
description of the function
INPUT:
OUPUT:
'''
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As my comments are a lot, would it be fine if I added every line of comments in docstring?
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You don't need to write all. Just descriptive explanation is ok.
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Example docstring
'''
Sort the array by finding the largest elements and swapping the elements according to the index.
INPUT:
singer_list: list of singers corresponding to play counts
OUTPUT:
sorted_singer_lsit: list of sorted singer lists by play counts
'''
| return singers_rating | ||
| # You remember largest variable above that calls for this function? Here we define it with the following code | ||
| def findLargest(singers_list): | ||
| #We assume the first value of singers' list as the largest value |
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write docstring instead of comments
Make a short description. You don't need to explain everything in the function in detail. You can just describe some points which might be confusing.
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Yes, sis I thought I could do . But I am concerned about other beginners who don't know at all about code. So, I took a lot of time to write line by line. How do you want to further suggest me?
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we should follow the correct coding style. As long as the code is clear enough, they will understand.
Check out the coding styles of python.
https://www.python.org/dev/peps/pep-0008/
https://www.python.org/dev/peps/pep-0257/
| #After updating our largest_index, return it to the function. Don't forget to look back at two skipped lines above :xD | ||
| return largest_index | ||
| #After applying selection sort algorithm, we add it to the variable name called favorite_singers | ||
| favorite_singers=selectionSort(singers_list) |
| # Then we print favorite_singers and get the following output | ||
| print(favorite_singers) | ||
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| Output:[230, 190, 178, 112, 90, 80] |
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what does this output mean? Please remove this if not necessary.
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It's sth code testers will get after they have run code in the editor. I think I had better write it in comment.
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They will get the output when they run. You can write the output in docstring output if you wish to.
For example.
'''
....
OUTPUT:
sorted_list: .....
Output [230, 190, 178, 112, 90, 80]
'''
| #We call findLargest function and search for largest value in the sigers' list and I recommend to look first at next third line | ||
| largest = findLargest(singers_list) | ||
| #We got the largest value by calling findLargest function below and we afterwards remove that largest value from singers_list and then add to our empty list declared above | ||
| singers_rating.append(singers_list.pop(largest)) |
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you can simply add singers_list[index] -> pop is not required here.
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sis, all this code exists in selection sort chapter of Grokking algorithm. What I changed is only names. Every line of code is the same
Here is the source code
def findSmallest(arr):
smallest = arr[0] Stores the smallest value
smallest_index = 0 Stores the index of the smallest value
for i in range(1, len(arr)):
if arr[i] < smallest:
smallest = arr[I]
smallest_index = I
return smallest_index
Now you can use this function to write selection sort:
def selectionSort(arr): Sorts an array
newArr = []
for i in range(len(arr)):
smallest = findSmallest(arr)
newArr.append(arr.pop(smallest))
return newArr
print selectionSort([5, 3, 6, 2, 10])
| #As we consider the first value of singers' list as the largest value, we make it as the largest index of 0 | ||
| largest_index = 0 | ||
| #We start from index 1 to the end within the length of singers' list | ||
| for i in range(1, len(singers_list)): |
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you don't need to compare everything from the 1 to the last index.
what you need to do is compare i+1 to the last index because 0 to 1 assumes to be sorted after one iteration is over.
| #After applying selection sort algorithm, we add it to the variable name called favorite_singers | ||
| favorite_singers=selectionSort(singers_list) | ||
| # Then we print favorite_singers and get the following output | ||
| print(favorite_singers) |
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if you want to give the variable names 'favourite_singers', the output should be singer names.
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Yes, I wanna output singers' names instead of list of values. I am still finding ways to do it ,sis. But if you have recommendation on how to do it, I'm looking forward to it.
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if you use a dictionary, instead of an array, you need to sort the dictionary instead of a list. (key-value pair)
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you can write lambda function to sort of key-value pair.
Added selection sort algorithm code to data structure and algorithm. Looking forward to feedback.