Exploring Three Alternatives to Traditional For Loop Statements

Python makes extensive use of for loops statements. For loops are used to repeatedly iterate over sequences, collections, and other iterable objects. The Python programming language has other methods for iterating through sequences besides for loops, though. In this article we examine three alternatives to for loop statements.

The Filter Function

Let's say we have a list of names, and we want to create a sublist of all the names in the list that have a length of 4. Instead of using a for loop to iterate over the list, we can use the filter() function. First, here is how the code would look if we used a normal for loop statement:

Even though this code works just fine, it is quite long for such a simple task.

Now, let's use the filter() function. The filter() function is a higher-order function that takes two arguments: a function and an iterable. It uses the criteria set by the function to filter the iterable. Below, we are using the filter() function with a lambda function to filter the list_of_names for names that have a length of 4:

You can see that with the filter() function we perform the same operations with fewer lines of code, making the code more concise and readable.

The Map Function

Let's say we have a list of strings of integers and want to convert them into integers, we can use the map() function instead of a for loop. Here is how the code will look like if we use a for loop statement.

You can see that the code is quite long for such a simple task.

The map() function is another higher order function that two arguments: a function and an iterable. We are going to pass the lambda function as an argument to the map() function The map() function will apply it to every element in the list. Here is the code using using the map() function:

You can see that our code is now more concise. Apart from helping us write code that is more concise, the map() function is optimized for performance. This makes our code not just easy to read but also often faster.

List Comprehension

Another alternative to for loops is list comprehension. List comprehensions are a concise and Pythonic way to create lists by applying an expression to each item in an iterable. A list comprehension will generate a list from an existing list. Let's say we have a list of numbers, and we want to return a list with each number divided by 2. Here is how the code will look if we use a for loop:

Now, when we use list comprehension instead of a for loop statement, the code becomes more concise. See below:

Conclusion

We have seen how these alternatives to for loops allow us to express the same operations with fewer lines of code, making code more concise and readable. In some cases, map() and filter() functions can be more efficient than for loops because they are optimized for performance. Please share this article and?subscribe?to this newsletter if you are not yet a subscriber. You can also follow me on?LinkedIn.

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