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In the following example:
def speak(volume):
def whisper(text):
print(text.lower() + ('.' * volume))
def yell(text):
print (text.upper() + ('!' * volume))
if volume > 1:
return yell
elif volume <= 1:
return whisper
func = speak(volume=10)
func('hello')
HELLO!!!!!!!!!! # <== obviously `10` is stored in `func` somewhere
Given func, how would I get the "volume"? Is there something within the func namespace which gives the value of 10? I thought perhaps it would be in func.__globals__ or func.__dict__ but it's in neither.
902
The term "closed-over" variable in that post means that the variable is not accessible by the caller of the function; it is neither seen nor modifiable from the context where the function is being called.
Closures are frequently used in JavaScript for object data privacy, in event handlers and callback functions, and in partial applications, currying, and other functional programming patterns.
Global variables live until the page is discarded, like when you navigate to another page or close the window. Local variables have short lives. They are created when the function is invoked, and deleted when the function is finished.
A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment). In other words, a closure gives you access to an outer function's scope from an inner function.
It makes it possible for a function to have " private " variables. The counter is protected by the scope of the anonymous function, and can only be changed using the add function. A closure is a function having access to the parent scope, even after the parent function has closed.
Closures in functional programming are the functions that are aware of their surroundings By this, I mean that a closure function has access to the variables and parameters defined in the outer scope.
In JavaScript, Closure means that an inner function always has access to the variables and parameters of its outer function, even after the outer function has returned. The closure is created when an inner function has access to its outer function variables and arguments. The inner function has access to –
The local variable text of the outer function is a non-local variable for the inner function which it can access but not modify. A closure is a function object (a function that behaves like an object) that remembers values in enclosing scopes even if they are not present in memory.
Below (the code below return 10)
func.__closure__[0].cell_contents
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