Foreach loop in python

Python foreach Loop

The “foreach” loop is used in programming languages like Java, C++, PHP, etc. to iterate over each element of a list, array, etc. In Python, there is no keyword similar to the “foreach” loop but there is a “for” loop keyword that is almost similar to “foreach”. The for loop or foreach loop both iterate over the sequence or collection of objects but the foreach loop iterates over the elements rather than maintaining a counter or iteration.

In this blog, we will demonstrate multiple ways to use the foreach loop in Python. The below contents will be discussed in detail with numerous examples:

• How to Create a Python foreach Loop?
• Method 1: Using for and in Expression
• Method 2: Using List Comprehension
• Method 3: Using map() Function

How to Create a Python foreach Loop?

To create a for each loop different methods are used in Python. These methods include the “for-in” statement, “list comprehension” and “map()” functions. We will discuss all these methods with appropriate examples:

Method 1: Using for and in Expression

The “for” and “in” expressions are used in the below code to achieve the functionality of for-each loop:

for i in [5, 10, 15, 20]: print(i)

The “for” and “in” expression is used to iterate over the given list and display the value of every element.

The for-each loop has been executed using the for and in expressions.

Method 2: Using List Comprehension

The following code uses list compression to create a foreach loop:

list_1 = [55, 45, 65, 75] new_list = [i+5 for i in list_1] print(new_list)

• In the list comprehension, for loop iterate over the given list and perform “i+1” computation for each element of the list.
• After operating on each element of the list the final list will be returned.

A new list is created by adding “5” to each element of the list.

Method 3: Using map() Function

The “map()” function can be used as an alternative to the “for each” loop in Python. Here is an example code:

list_value = [1, 2, 3, 4, 5] def sum(x): return x+5 output = map(sum, list_value) print(list(output))

• The list named “list_value” is created in the program.
• The function named “sum” is defined that will add 5 to every element of the list.
• The “map()” function is used to get a map object after applying the stated function to each element value of the list.
• The “map()” function returns the map object iterator which is passed as an argument to the list to return a new list iterator.

The map() function successfully applies the “sum” function to the given list element.

Conclusion

The “for-in” expression, “list comprehension” and “map()” function is used to perform the “for each” loop on every element of the given iterator in Python. There is no keyword similar to “for each” in Python. However, some methods perform a similar functionality just like the “for-each” loop. The “map()” function is used to iterate over the sequence and apply a function to each element of the sequence. This guide delivered various ways to perform Python for-each loop.

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Python foreach Loop

💡 Question: Does Python have a for each or foreach loop? If so, how does it work? If not, what is the alternative?

This article will shed light on these questions. I’ll give you the summary first and dive into the details later:

Python has three alternatives to the “for each” loop:

You’ll learn about those alternatives in the following paragraphs, so keep reading!

Let’s get started with the most important question:

What is a “Foreach Loop”?

Definition: A foreach or for each loop is a programming control flow statement for iterating over elements in a sequence or collection. Unlike other loop constructs, the foreach loop iterates over all elements rather than maintaining a counter, loop variable, or checking a condition after each loop iteration.

Here are three examples of a foreach loop in three different programming languages PHP, C#, and Perl:

// PHP foreach ($set as $value) < // Do something to $value; >// C# foreach (String val in array) < console.writeline(val); >// Perl foreach (1, 2, 3, 4)

Does Python have a foreach Loop?

The Python language doesn’t support the keywords foreach or for each loops in a literal syntactical way. However, “for each” in Python is done using the “for … in …” expression. For example, to iterate over each element in the list [10, 20, 30] in Python, you’d write for x in [10, 20, 30] .

Here’s a full Python code example with semantical equivalence to a “foreach” statement:

# 'foreach' or 'for each' in Python is done using 'for' for x in [10, 20, 30]: print(x)

🌍 Learn More: Feel free to check out our full article on Python loops on the Finxter blog.

“For Each” Meaning “Apply Function to Each Element”

If you’re reading this and you haven’t been satisfied with the answers provided so far, chances are that you’re really searching for the map function functionality in Python.

Many programming languages with “for each” support provide a syntax that applies a function to each element of an iterable like so:

# Other programming languages: foreach(function, iterable)

This can be done in Python by means of the map() function:

# Python: map(function, iterable)

Here’s a simple example of how you’d use the map() function in Python that applies the function f to each element of the list [1, 2, 3] , incrementing each of its elements by 1 to obtain [2, 3, 4] :

lst = [1, 2, 3] def f(x): return x + 1 print(map(f, lst)) # [2, 3, 4]

You can watch my explainer video on map() in the following video:

While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.

To help students reach higher levels of Python success, he founded the programming education website Finxter.com that has taught exponential skills to millions of coders worldwide. He’s the author of the best-selling programming books Python One-Liners (NoStarch 2020), The Art of Clean Code (NoStarch 2022), and The Book of Dash (NoStarch 2022). Chris also coauthored the Coffee Break Python series of self-published books. He’s a computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.

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Is Foreach In Python Available?

Foreach loop is available in PHP, Java, JavaScript, etc. If you’re starting with Python, you might wonder if foreach in Python is available? Or if there is a loop similar to foreach. So in this article, we will help you better understand.

What is foreach?

Foreach in C#, PHP, … is an iterative construct that allows us to iterate over an array or a set.

• foreach traverses the array without an index.
• foreach iterates through the elements in the array.
• foreach is only used to traverse iterable objects and cannot traverse other data types.

We’ll find it convenient if we’ve worked with foreach in another language.

But the most important thing in this article is that foreach is not included in Python. It means that Python does not support keywords like forEach or foreach.

So, what should we use instead of foreach in Python?

You can replace foreach with for … in … aka For Loop in Python. Not only that, there are so many other ways to replace foreach. We will introduce you right now.

Use for … in … loop

Before reading on, you can read more about the syntax of For Loop in Python here.

There is no foreach in Python, but if you want, you can create a foreach function yourself using for . in . like this:

def forEach(iterable, function): # Using for . in . for x in iterable: function(x) websites = ['learnshareit.com', 'facebook.com', 'twitter.com', 'google.com'] forEach(websites, print)

learnshareit.com facebook.com twitter.com google.com

Loop through with the index

If you need to work with the index in For Loop, use range() and len() functions. These 2 functions are used a lot in Python loops. See the sample code below to know how to use them.

websites = ['learnshareit.com', 'facebook.com', 'twitter.com', 'google.com'] # Combine range() and len() in the for loop for i in range(len(websites)): print(i, websites[i])

0 learnshareit.com 1 facebook.com 2 twitter.com 3 google.com

Use List Comprehension

List Comprehension is a quick way to filter or edit a list. It helps you write more concise and readable code.

We can use List Comprehension to quickly traverse a list and work with each element of the list. Like this:

websites = ['learnshareit.com', 'facebook.com', 'twitter.com', 'google.com'] # Uppercase the element of the websites [print(website.upper()) for website in websites]

LEARNSHAREIT.COM FACEBOOK.COM TWITTER.COM GOOGLE.COM

Summary

As mentioned at the beginning of the article, there is no foreach in Python. However, there are shorter and easier-to-use ways than foreach in other languages ​​to iterate over an object.

Hope the knowledge in the article will help you become a Python developer in the future.

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