Nested function
- Function defined inside another function –>
nested function
- Nested functions are able to access variables of the enclosing scope.
def print_msg(msg):
def printer():
print(msg)
printer()
print_msg("Hello")
# Output: Hello
Closure function
- A Closure is a function object that
remembers values in enclosing scopes
even if they are not present in memory. - The function innerFunction has its scope only inside the outerFunction.
- But with the use of closures we can easily extend its scope to invoke a function outside its scope.
# Calling inner fxn outside the scope
def print_msg(msg):
def printer():
print(msg)
return printer
another = print_msg("Hello")
another()
# Output: Hello
Python program to illustrate nested
functions
def outerFunction(text):
def innerFunction():
print(text)
innerFunction()
outerFunction('Hey!')
Python program to illustrate closures
def outerFunction(text):
text = text
def innerFunction():
print(text)
return innerFunction
# returning function WITHOUT parenthesis
myFunction = outerFunction('Hey!')
myFunction()
Python program to illustrate closures
def logger(func):
def log_func(*args):
print(func.__name__, args, end='--> ')
print(func(*args))
return log_func
# returning function WITHOUT parenthesis
def add(x, y):
return x+y
def sub(x, y):
return x-y
add_logger = logger(add)
sub_logger = logger(sub)
add_logger(3, 3) # add (3, 3)--> 6
add_logger(4, 5) # add (4, 5)--> 9
sub_logger(10, 5) # sub (10, 5)--> 5
sub_logger(20, 10) # sub (20, 10)--> 10