Lambda Function in Python – Properties & Why Use It?

Python Lambda function is an anonymous function that is defined without even a name. Modern computer languages, such as Python as well as other programming languages such as C, C#, and Java, allow us to avoid using the “def” keyword to declare the function. Rather, the lambda keyword is used to declare anonymous functions. Lambda functions can take an infinite number of parameters but can only return a single value in the form of an expression.

A short piece of code is included in the anonymous function. It replicates C and C++ inline functions, but it isn’t actually an inline function.

What is Lambda Function in Python?

A lambda function returns an object and is a short anonymous function. This returned object is typically allocated to a variable or utilized as a part of larger functions.

A lambda function can be defined using the lambda keyword rather than the traditional ‘def” keyword for generating functions.

“lambda arguments expression” is the syntax for the lambda function. There could be any number of parameters, but only one expression can be used. There is no return statement in the function syntax, which is usually present. Even if there is no return statement, the function will simply return the value of the expression.

The Requirement for Lambda Functions

There are at least three explanations for this:

  • When compared to a conventional python function declared with the def keyword, lambda functions decrease the number of lines of code. However, even functions declared using def could be defined in a single line, thus this isn’t entirely true. Def functions, on the other hand, are usually written on multiple lines.
  • They’re typically utilized whenever a function is only needed for a short amount of time, and they’re frequently employed inside other functions like filter, map, and reduce.
  • You might define a function and execute it right at the conclusion of the declaration with the lambda function. Def functions can’t be used for this.

Why Lambda Function in Python?

At the interpreter level, lambdas are processed the same as normal functions. Lambdas, in a sense, provide a minimal syntax for creating functions that return a single expression.

When to utilize lambdas or when to ignore them is a good idea. A lot of the basic concepts used by python developers while writing lambdas are discussed here.

Because Python offers a programming paradigm (or style) known as functional programming, one of the most prominent use cases for lambdas is in functional programming.

It allows you to pass a function to another function as a parameter (for example, in map, filter, etc.). In such circumstances, lambdas provide a beautiful solution by allowing you to create a one-time function and give it as a parameter.

Lambda functions have the following characteristics:

  • They can take numerous arguments but only return one expression. The result produced by the lambda function is the expression in this case.
  • Syntactically, lambda functions can only return a single expression.
  • You can utilize them inside other functions as anonymous functions.
  • There is no need for a return statement in lambda functions since they always yield a single expression.

Where Should Lambda Expressions be Used?

Lambdas are a type of function that returns a single expression and has a shorter syntax. Lambdas are among the most common use cases in a functional programming paradigm because Python supports them. By constructing a one-time function and giving it as a parameter, lambdas provide an excellent way to give functions as parameters to another function.

Lambda Filtering functions ()

The filter function is used to choose certain elements from a list of elements. This function uses an iterator, such as lists, sets, tuples, and so on.

The elements that can be chosen are limited by a predetermined limitation. It requires two parameters:

  • The filtering restriction is defined by this function.
  • A series (any iterator, for example, lists, tuples, etc)

Lambda Functions in the map()

For every element in a series, the map function is used to perform a certain operation. It takes two parameters, just like filter():

  • A function that specifies how the operations on the elements will be carried out.
  • A series or several sequences

Lambda Reduced functions ()

Reduce is similar to map() in that it applies an operation for every element in some kind of sequence. However, it works differently from the map function. To compute an output, the reduce() function must do the following steps:

Step 1:

Apply the defined operation to the sequence’s primary two members.

Step 2:

Save the outcome

Step 3:

Carry out the operation with the saved result, which is the sequence’s next element.

Step 4:

Continue until there are no more elements.

It also has two additional parameters: A function that specifies how operations should be carried out and a series of events (any iterator like lists, tuples, etc.).

Python Lambda Function Syntax

The python lambda function allows a series of arguments, however, it only calculates & returns a single expression.

  • Python Lambda Syntax could be utilized whenever the incorporated objects in the function are mandatory.
  • It is essential to keep in mind that lambda functions are syntactic and semantic, being constrained to one expression.
  • It also possesses several apps in specific programming domains.

Advantages of Using Lambda Function in Python

Lambda functions are shorthand functions in Python that are frequently used when a programmer is feeling lazy and doesn’t feel like completely specifying a function (we’re not judging). Despite the fact that they don’t appear like a typical function that you’d declare with the def keyword, they work in a similar fashion. The primary distinction is that they would only run one phrase at a time. Anonymous functions are another name for lambda functions.

Lambda functions allow the user to enter short, one-time functions in your code, saving you time and space. They’re also useful when calling functions like Map() and Filter() that expect a function as an input for a callback. But what exactly is a lambda function? What’s more, how do you put them into practice in your code? Continue reading, and we’ll try to explain it. Unlike lambda functions, we’ll go over everything in great depth, and perhaps help you improve your code in the future.


Lambda functions will not revolutionize your Python code in terms of functionality; you can’t do anything about them that you can’t accomplish without them. However, by employing them, you can improve the efficiency, compactness, and readability of your code. When processing data in a threaded context, functional programming techniques will come in handy. Lambda functions will not always be the most appropriate right tool. Understanding which tools are available are ideal for the job is an important part of becoming a well-rounded programmer.

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