Python Lambda Functions

In Python, lambda functions are a way to create small, anonymous functions (i.e., functions without a name). They are used when you need a simple function for a short period and don’t want to formally define it using def.

💡Lambda Function Syntax

The lambda function syntax is as follows:

lambda arguments: expression

• lambda is the keyword.
• arguments are the inputs to the function.
• expression is what gets returned automatically.

✅ Example: Basic Lambda

add = lambda x, y: x + y
print(add(3, 5)) # Output: 8

This is equivalent to:

def add(x, y):
 return x + y

🔹 Why Use Lambda Functions?

• Used for short tasks where a full function is not needed.
• Often used with functions like map(), filter(), and sorted().

🔸 Examples

map() – Apply function to all elements

nums = [1, 2, 3, 4]
squares = list(map(lambda x: x*x, nums))
print(squares) # Output: [1, 4, 9, 16]

filter() – Filter values based on condition

nums = [1, 2, 3, 4, 5, 6]
even = list(filter(lambda x: x % 2 == 0, nums))
print(even) # Output: [2, 4, 6]

sorted() – Sort by custom key

names = ['apple', 'banana', 'cherry']
sorted_names = sorted(names, key=lambda x: len(x))
print(sorted_names) # Output: ['apple', 'banana', 'cherry']

⚠️ Limitations

• Only one expression is allowed (no multiple statements).
• Not suitable for complex logic.

✅ Summary Table

Feature	Regular Function	Lambda Function
Named	Yes (def)	No (anonymous)
Syntax	Multi-line possible	One-line only
Use Case	Complex or reusable code	Short, throwaway logic
Return keyword	Required (return)	Not required

 

Python Tutorials

Python Tutorial on this website can be found at:

• https://www.testingdocs.com/python-tutorials/