What Are Loops?

Definition

A loop is a control structure that performs a set of instructions a specific number of times. Loops solve the problem of writing the same set of instructions repeatedly. We can specify the number of times we want the code to execute.

One of the biggest applications of loops is traversing data structures, e.g., lists, tuples, sets, etc. In such a case, the loop iterates over the elements of the data structure while performing a set of operations each time.

Just like conditional statements, a loop is classified as a control structure because it directs the flow of a program by making varying decisions in its iterations.

Loops are a crucial part of many popular programming languages, such as C++, Java, and JavaScript.

Loops in Python

There are two types of loops that we can use in Python:

1. The for loop

2. The while loop

Both achieve repetition, however, they differ slightly in terms of usage.

• Use a for loop when you know the number of repetitions beforehand. For instance, when iterating over a sequence of elements in a list.

• Use a while loop when you need to repeat a block of code based on a condition that might change within the loop itself. For example, in a scenario where the program repeatedly takes input from the user and stops when the input meets a predefined criteria.