Python Lambda Functions

A lambda function in Python is an anonymous function that can take any number of arguments but can return only one expression. A lambda function is defined by using the ‘lambda’ keyword.

Syntax

lambda arguments: expression

In the syntax:

arguments are any value passed

expression is the returned value

Example:

addition = lambda x, y : (x + y)
print(addition(4,7))

Output:

11

In the above example, the lambda function is represented by lambda x, y : (x + y). X, y are the arguments and (x+y) is the returned value. It produces a function object which is then stored in the variable ‘addition’. So ‘addition’ can be further used as a standard Python function.

Using if – else with lambda functions

We can also put conditional statements if – else to return a result based on certain condition in lambda functions. Consider this example.

findMaximum = lambda x,y : x if(x > y) else y
print(findMaximum(1,4))

Output:

4

Uses of lambda functions

• A lambda function can be used inline, so when there is not too much complex logic, you don’t need to define a regular function.
• A regular function can be defined once and used multiple times. On the other hand a lambda function works best when the logic is to be applied only once.
  

Pros

• It’s syntax is much simpler than a regular function.
• It’s an ideal choice for performing an operation that is to be done only once.

Cons

• It can’t have any variable assignment. For example lambda x : x = 1 will throw an error.
• It cannot perform multiple operations.