# Lambda function in Python list

A lambda function in Python is a concise way to create small, anonymous functions. They are often used in combination with functions like `map`, `filter`, and `sorted` to perform quick operations on lists.

Here’s the syntax of using a lambda function in Python with lists:

`map` with a Lambda Function:

``new_list = map(lambda argument: expression, original_list)``

`filter` with a Lambda Function:

``````filtered_list = filter(lambda argument: condition, original_list)
``````

`sorted` with a Lambda Function:

``````sorted_list = sorted(original_list, key=lambda argument: expression)
``````

In each case, the lambda function is defined inline using the `lambda` keyword, followed by the arguments and the expression or condition to be applied.

## Lambda function in Python list example

Here’s how you can use lambda functions with lists:

1. Using `map` with a Lambda Function: The `map` function applies a given function to all items in an input list and returns an iterator.

``````numbers = [1, 2, 3, 4, 5]
squared_numbers = map(lambda x: x ** 2, numbers)

result = list(squared_numbers)  # Convert the iterator to a list
print(result)
``````

2. Using `filter` with a Lambda Function: The `filter` function applies a given function to all items in an input list and returns an iterator with the items that satisfy the function’s condition.

``````numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
even_numbers = filter(lambda x: x % 2 == 0, numbers)

result = list(even_numbers)  # Convert the iterator to a list
print(result)
``````

3. Using `sorted` with a Lambda Function: The `sorted` function can be used to sort a list based on a specific criterion defined by a lambda function.

``````words = ["apple", "banana", "cherry", "date", "elderberry"]
sorted_words = sorted(words, key=lambda x: len(x))

print(sorted_words)
``````

Output:

Note: Lambda functions are convenient for simple operations, for more complex or reusable operations, it’s better to define regular named functions using the `def` keyword.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.