What is local and nonlocal in python w3schools

What is local and nonlocal in python w3schools

I'll respond in English as you requested. Here's the information about local and non-local variables in Python from W3Schools:

Local Variables

In Python, a variable that is defined inside a function or a block of code (such as an if statement) is considered local to that scope. Local variables are only accessible within the scope where they are defined.

Here's an example:

def my_function():
x = 10  # local variable
my_function()
print(x)  # prints None

As you can see, when we try to print x outside of the function, Python returns None, which means that the local variable is not accessible outside of its scope.

Non-Local Variables

On the other hand, non-local variables are those that are defined in a parent scope (i.e., an outer scope) and are accessible from within a child scope (i.e., an inner scope).

Here's an example:

x = 5
def my_function():
print(x)  # prints 5
my_function()
print(x)  # also prints 5

In this case, x is defined outside of the function and is accessible within the function. This is because Python uses a mechanism called "dynamic scoping" to determine which variables are in scope.

The global Keyword

If you want to modify a non-local variable from within a local scope, you need to use the global keyword. The global keyword tells Python that the variable should be treated as global and not as local.

Here's an example:

x = 5
def my_function():
global x
x = 10
my_function()
print(x)  # prints 10

In this case, we use the global keyword to indicate that we want to modify the non-local variable x. This allows us to change the value of x from within the function.

Conclusion

To summarize:

I hope this explanation helps!

What is local and nonlocal in python with example

I apologize for the misunderstanding earlier. Here's a detailed explanation of local and nonlocal variables in Python, along with examples:

Local Variables:

In Python, local variables are defined within a specific scope, such as a function or a block of code. They can only be accessed and modified within that scope. Local variables are created when the function is called or executed, and they cease to exist when the function returns.

Example:

def my_function():
x = 5  # local variable
print(x)  # prints 5
my_function()
print(x)  # NameError: name 'x' is not defined

In this example, x is a local variable defined within the my_function() scope. When we try to access x outside the function, Python throws a NameError, indicating that x is not defined in the current scope.

Nonlocal Variables:

Nonlocal variables are variables from an outer scope (parent function or block) that can be accessed and modified within an inner scope (child function or block). The term "nonlocal" refers to the fact that these variables are not local to the inner scope, but rather are shared with it.

Example:

def outer_function():
y = 10  # nonlocal variable
def inner_function():
nonlocal y  # declare y as a nonlocal variable
y += 5  # modify y
print(y)  # prints 15
inner_function()
print(y)  # prints 15
outer_function()
print(y)  # prints 15

In this example, y is a nonlocal variable defined in the outer function. Within the inner function, we use the nonlocal keyword to declare that y is a nonlocal variable from the outer scope. We can then modify and access y within the inner function.

Key Differences:

Local variables:

Nonlocal variables:

Best Practices:

When working with local and nonlocal variables, keep the following best practices in mind:

By understanding the concepts of local and nonlocal variables, you can write more effective and efficient Python code that leverages the power of scope management.