Understanding the Basics of Sorted and Unsorted Lists

The check for sorted list in python is straightforward. It involves comparing two adjacent elements in the given list using a simple comparison operator, and repeating this process throughout all elem …

Updated November 22, 2023

The check for sorted list in python is straightforward. It involves comparing two adjacent elements in the given list using a simple comparison operator, and repeating this process throughout all elements in the list.

Basics

Python has built-in methods for checking whether a list is sorted or not. Here are some examples to demonstrate them:

``````# Unsorted list
unsorted_list = [10, 23, 45, 6, 89]
print(all(unsorted_list[i] <= unsorted_list[i + 1] for i in range(len(unsorted_list) - 1))) # False

# Sorted list
sorted_list = [10, 23, 45, 60, 89]
print(all(sorted_list[i] <= sorted_list[i + 1] for i in range(len(sorted_list) - 1))) # True
``````

In the first example, `all()` is used to check if all elements in the list are `True` or not. If any element is `False`, it returns `False`.

The `i` variable represents an index of a current number from our list and `i + 1` represents the next number in the list. The condition checks if each number is less than or equal to the next one (`unsorted_list[i] <= unsorted_list[i + 1]`). If it’s true for all numbers, it will return `True`, indicating that the list is not sorted. Otherwise, it returns `False`.

In the second example, we have a sorted list and using same logic checks if all elements in the list are less than or equal to the next one which returns `True` indicating that the list is sorted.

So when we say “How to check if a list is sorted in Python”, it’s not about programming but more about logical thinking.