Contents
- What is a global variable in Python?
- How to create a global variable in Python?
- How to access a global variable in Python?
- How to change the value of a global variable in Python?
- How to delete a global variable in Python?
- Examples of using global variables in Python
- Benefits of using global variables in Python
- Drawbacks of using global variables in Python
- When to use global variables in Python?
- How to avoid using global variables in Python
Python global variables are variables that are defined outside of a function. In this tutorial, we will show you how to use global variables in Python.
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What is a global variable in Python?
A global variable is a variable that is defined outside of a function. Global variables can be used by any function in your Python program.
To create a global variable, you can just assign a value to a variable outside of any function:
“`
x = “global”
“`
You can then use the global variable inside of any function:
“`
def myfunc():
print(“inside myfunc: ” + x)
myfunc() # this will print “inside myfunc: global”
“`
How to create a global variable in Python?
A global variable is a variable that is accessible in all scopes throughout your Python program. You can create a global variable by using the “global” keyword. Let’s take a look at an example:
In the following example, we have created a global variable called “x” and assigned it the value of 10. We can then access this variable in any scope in our program:
“`python
x = 10
def foo():
print(x) # Prints 10
def bar():
print(x) # Prints 10
foo()
bar()“`
How to access a global variable in Python?
A global variable is a variable that is defined in the main body of a code. Python automatically makes all variables in code defined in the main body global. So, you can access global variables without having to define them as global variables.
There are two ways to access a global variable in Python:
-Using the global keyword: You can use the global keyword to explicitly define a variable as being a global variable. When you do this, you can then access the variable anywhere in your code.
-Without using the global keyword: You can implicitly make a variables in your code global by accessing it outside of any functions. When you do this, Python automatically makes thevariable global.
To learn more about Python, visit our Python tutorial page, where you will find more information on how to use Python, including example code and practice exercises.
How to change the value of a global variable in Python?
Global variables are the one that are defined and declared outside a function and we use global keyword to create it.
That means, global variable can be accessed inside or outside of the function.
We use global keyword to read and write a value to a global variable.
If you want to change the value of a global variable inside a function, then you must use global keyword.
Only after using the global keyword, we can assign a value to the global variable.
## Title: How To Use Local Variables In Python?
## Heading: What is the scope of local variables in Python?
## Expansion:
A local variable is only accessible within the scope it was created in. A scope is basically a region of your code where a particular variable name exists and can be used. In Python, there are fourprimary places where your variables can exist:
– Global scope: A variable with global scope is defined in the main body of your code and can be used by any code within your program.
– Function/method scope: A variable with function/method scope is defined within a function or method and can only be used by code within that particular function or method.
– Class scope: A variable with class scope is defined within a class and can only be used by code within that particular class.
How to delete a global variable in Python?
Python doesn’t support global variables in the sense that other languages do.
If you declare a variable outside of a function, it is available throughout your program, but it is not recognized as a global variable by Python.
In order to control a global variable from within a function, you must first use the keyword global to tell Python that you want to use the global variable, and then use the name of the variable.
For example:
“`python
def myfunc():
global x
x = 300
“`
Examples of using global variables in Python
Global variables are variables that are declared outside of a function. They can be used inside of a function, but their scope is limited to the function they are declared in. In order to use a global variable inside of a function, you must first declare it as global inside of the function. For example:
“`
my_global_variable = 10
def some_function():
global my_global_variable
my_global_variable += 1
print(my_global_variable)
some_function() # Will print 11
“`
Benefits of using global variables in Python
Python global keyword is used to define a variable inside a function as global. … By default, all the variables declared inside a function are local in scope to that function. If we want to make those variables global, then we need to use the keyword “global”, as shown in the example below.
Drawbacks of using global variables in Python
Global variables are namespace-less and thus present a problem when used in modules. Any variable declared outside a function is global. When we try to modify such a variable inside a function, the change is visible outside. This can be problematic if the same name is being used in different places for different purposes.
In addition, global variables tend to make code difficult to read and debug. It makes it hard to figure out where a particular value is coming from or being used.
When to use global variables in Python?
As a general rule, you should avoid using global variables in Python. In fact, many experienced Python programmers will tell you that global variables are almost always a bad idea.
There are a few cases where global variables can be useful, but they should be used sparingly and with caution. In general, it is better to use local variables unless you have a good reason to do otherwise.
One case where global variables can be helpful is when you need to share data between different parts of your program. For example, if you have a list of items that need to be processed by different functions, you could put that list in a global variable so that all the functions can access it.
Another case where global variables can be useful is when you want to make sure that certain data is always available, even if the user tries to delete it or change it. For example, if you have a list of default settings for your program, you could put those in global variables so that they can’t be changed by the user.
However, there are some risks associated with using global variables. First of all, they can make your code harder to understand. If you use too many global variables, it can be difficult to keep track of what each one is used for and how it interacts with other parts of your code.
Second, global variables can also make your code harder to change and maintain. If you need to make a change to a global variable, you may have to change other parts of your code as well so that everything still works correctly. This can quickly become confusing and difficult to keep track of.
Finally, global variables can cause problems if two different parts of your code try to use the same variable name for different purposes. This can lead to unpredictable results and errors in your code.
Overall, then, it is best to avoid using global variables unless there is a good reason to do so. If you do need to use them, make sure that you understand the risks involved and take care to use them wisely.
How to avoid using global variables in Python
It is considered best practice in Python to avoid using global variables. Global variables can make your code difficult to read and debug, and can cause problems if multiple files try to use the same global variable. Instead, it is better to use local variables that are only visible within the scope of the function or class where they are defined.