Loops in Python: What You Need to Know About Them?

In the context of programming, loops as a concept exist in all languages. They are a tool that facilitates the implementation of iterations in programs. Simply put, loops in Python and in most programming languages are used to execute the same block of code two or more times.

Loops are generally existing features in all programming languages and provide similar basic functionality, but their implementation and syntax differ depending on the code. In this article, we will look at what loops are, what types exist, and what loops are in Python.

Currently, Python is the fifth most popular programming language in the world. It is widely used in big data, artificial intelligence, and machine learning, and also has many internal applications for web development.

Consequently, Python continues to evolve, and programmers with experience in this language are becoming increasingly sought after by companies. Therefore, taking Python programming courses can help improve your employment prospects.

What Are Loops in Python?

In Python, code is executed sequentially. In other words, if what has been programmed consists of several lines, then execution will start from the first line, move to the second, and so on.

However, there are cases where this is not ideal, even if a certain block needs to be repeated. When is this necessary? We'll discuss that later, but it is usually related to the need to satisfy a condition. Thanks to loops in Python, you can make these code blocks repeat during program execution.

In programming, there are various types of loops. While other languages can have up to three different types, Python has two main types:

'For' Loops
'For' loops are based on iterators that iterate over all elements of iterable objects: lists, tuples, strings. They repeatedly execute a block of code depending on the number of elements contained in the iterable object.

'While' Loops
'While' loops execute the blocks of code they affect as long as the loop condition is true. The 'while' loop repeats until the condition is met a certain number of times.

Despite similarities with if statements, the 'while' loop in Python is executed multiple times, whereas if is executed only once.

How to Execute Loops in Python

In the case of both for loops and while loops, execution occurs when the given condition is true. If it is false, the loop does not execute; if true, an iteration occurs and the block of code repeats a certain number of times:

Start: a loop begins in Python with for<elem> in <iterable>: <code block> or While (condition): expression (code block).
Condition: if the condition is true, the code block iterates and executes again. If the condition is false, the program continues normal sequential execution.
After the loop starts, it will execute until the condition declared in the code becomes false. At that point, the program continues sequential execution.

Another important feature of loops in Python is that 'for' and 'while' loops can work as nested loops. What are nested loops in Python? Essentially, this term means using one or more loops inside another loop. That is, to solve complex problems in the process of software development, multiple loops are combined into one.

How to Create Loops in Python

As we already said, Python offers two types of loops, each with its own syntax and created in different ways:

• 'While' loops are created using the following syntax: While (condition): expression (code block). The expression must be checked because it becomes true during loop execution. At each iteration of the loop, this expression will be checked. When it becomes false, the loop ends.
• 'For' loops are created as follows: for<elem> in <iterable>: <code block>. In this case, elem denotes the variable with which the iterator begins, and iterable is the element on which the variable applies the loop. The loop will repeat until all values in the sequence of elements of the iterable variable are exhausted.

Additionally, loops in Python can be controlled. The following statements are used for this:

• Break: terminates the loop, breaking out of it.
• Continue: skips all code below and returns to the beginning of the loop.

If the loop termination is not properly specified in Python, an infinite loop is created. That is, the program constantly executes the same piece of code. This can be an error, but infinite loops can be programmed for specific purposes.