Anonymous Functions: lambda

• anonymous function expressed as a single statement.

Syntax (?)

lambda argument1, argument2 : expression

def edit_story(words, func):
    for word in words:
        print(func(word))
stairs = ['thud', 'meow', 'thud', 'hiss']
def enliven(word):
    return word.capitalized() + '!'

edit_story(stairs, enliven)

# lambda version
edit_story(stairs, lambda word: word.capitalized() + '!')

Testing Logic

Ensure your tests cover various scenarios:

Empty list:

• What happens when words is empty? No function:
• How does the function behave if func is missing or invalid?

pytesting

import pytest

def edit_story(words, func):
    for word in words:
        print(func(word))
stairs = ['thud', 'meow', 'thud', 'hiss']

def enliven(word):
    return word.capitalize() + '!'

def test_edit_story_with_function():
    # Arrange
    expected_output = ['Thud!', 'Meow!', 'Thud!', 'Hiss!']
    # Act
    edit_story(stairs.copy(), enliven)  # Don't modify original list
    # Assert -  This part needs to be adjusted, as edit_story prints but doesn't return anything. 
    # Use a mock or capture output to assert the printed values.

def test_edit_story_with_lambda():
    # Arrange
    expected_output = ['Thud!', 'Meow!', 'Thud!', 'Hiss!']
    # Act
    edit_story(stairs.copy(), lambda word: word.capitalize() + '!')  # Don't modify orig_list
    # Assert -  Similarly, need to handle the printed output here.

---

import pytest
from unittest.mock import patch

def edit_story(words, func):
    for word in words:
        print(func(word))

stairs = ['thud', 'meow', 'thud', 'hiss']

def enliven(word):
    return word.capitalize() + '!'

@patch('__main__.print')
def test_edit_story_with_function(mock_print):
    # Arrange
    expected_output = ['Thud!', 'Meow!', 'Thud!', 'Hiss!']
    # Act
    edit_story(stairs.copy(), enliven)
    # Assert
    mock_print.assert_has_calls([pytest.approx(call(output)) for output in expected_output])

# Similar test with lambda, using mock_print.assert_has_calls()

---

x = lambda a, b: a * b
print(x(5, 6))
# OUTPUT
30

"""doubles the number you send in"""
1 def myfunc(n):
2  return lambda a : a * n
3
4 mydoubler = myfunc(2)
5 
6 print(mydoubler(11))