How to Efficiently Determine if a List is Sorted in Python?

Efficiently Determining List Order in Python

In Python, you may encounter scenarios where it's crucial to determine the order of elements within a list. Checking the sorted status of a list is a common task, especially for data processing and validation. Rather than resorting to manual comparisons, Python offers elegant and efficient solutions to ascertain whether a list is sorted.

One of the most direct ways to check for sortedness is to utilize the all() function in conjunction with a generator expression. This approach provides a comprehensive understanding of list order with concise code:

<code class="python">all(l[i] <= l[i+1] for i in range(len(l) - 1))

The generator expression iterates over each consecutive pair of elements in the list, comparing them to determine ascending order. The all() function evaluates the outcome of each comparison, returning True if all pairs adhere to the specified condition (ascending order in this case).

To check for descending order, simply adjust the comparison operator to >=:

<code class="python">all(l[i] >= l[i+1] for i in range(len(l) - 1))</code>

For Python 2 compatibility, replace range with xrange in both expressions.

The above is the detailed content of How to Efficiently Determine if a List is Sorted in Python?. For more information, please follow other related articles on the PHP Chinese website!