#### Selection Sort

and 48 more contributors
```"""
This is a pure Python implementation of the selection sort algorithm

For doctests run following command:
python -m doctest -v selection_sort.py
or
python3 -m doctest -v selection_sort.py

For manual testing run:
python selection_sort.py
"""

def selection_sort(collection):
"""Pure implementation of the selection sort algorithm in Python
:param collection: some mutable ordered collection with heterogeneous
comparable items inside
:return: the same collection ordered by ascending

Examples:
>>> selection_sort([0, 5, 3, 2, 2])
[0, 2, 2, 3, 5]

>>> selection_sort([])
[]

>>> selection_sort([-2, -5, -45])
[-45, -5, -2]
"""

length = len(collection)
for i in range(length - 1):
least = i
for k in range(i + 1, length):
if collection[k] < collection[least]:
least = k
if least != i:
collection[least], collection[i] = (collection[i], collection[least])
return collection

if __name__ == "__main__":
user_input = input("Enter numbers separated by a comma:\n").strip()
unsorted = [int(item) for item in user_input.split(",")]
print(selection_sort(unsorted))
```

#### Problem Statement

Given an unsorted array of n elements, write a function to sort the array

#### Approach

• select the smallest element from the array
• put it at the beginning of the array
• then select the smallest array from the remaining unsorted list
• append it to the sorted array at the beginning
• keep doing this for every element of the array
• repeat the above process n times

#### Time Complexity

`O(n^2)` Worst case performance

`O(n^2)` Best-case performance

`O(n^2)` Average performance

#### Space Complexity

`O(1)` Worst case

#### Example

``````arr[] = {80, 10, 40, 30}
Indexes: 0   1   2   3

1. Index = 0
Select the minimum number from the array (between index 0-3), ie, 10
2. Swap 10  and 80 (arr)
3. The array now is {10, 80, 40, 30}

4. Index = 1
Select the minimum number from the array (between index 1-3), ie, 30
5. Swap 30 and 80 (arr)
6. The array now is {10, 30, 40, 80}

7. Index = 2
Select the minimum number from the array (between index 2-3), ie, 40
8. Swap 40 and 40 (arr)
9. The array now is {10, 30, 40, 80}

The array is now sorted.
``````  