GeezerVison is showing github.com — learn-python/src/functions/test_lambda_expressions.py at master · santoshpy/learn-python

Expand file tree

test_lambda_expressions.py

Copy path

More file actions

34 lines (24 loc) · 1.31 KB

Copy path

34 lines (24 loc) · 1.31 KB

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

"""Lambda Expressions

@see: https://docs.python.org/3/tutorial/controlflow.html#lambda-expressions

Small anonymous functions can be created with the lambda keyword. Lambda functions can be used

wherever function objects are required. They are syntactically restricted to a single expression.

Semantically, they are just syntactic sugar for a normal function definition. Like nested function

definitions, lambda functions can reference variables from the containing scope.

"""

def test_lambda_expressions():

"""Lambda Expressions"""

# This function returns the sum of its two arguments: lambda a, b: a+b

# Like nested function definitions, lambda functions can reference variables from the

# containing scope.

def make_increment_function(delta):

"""This example uses a lambda expression to return a function"""

return lambda number: number + delta

increment_function = make_increment_function(42)

assert increment_function(0) == 42

assert increment_function(1) == 43

assert increment_function(2) == 44

# Another use of lambda is to pass a small function as an argument.

pairs = [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four')]

# Sort pairs by text key.

pairs.sort(key=lambda pair: pair[1])

assert pairs == [(4, 'four'), (1, 'one'), (3, 'three'), (2, 'two')]