Defining Lists as Global Variable in Python

Defining Lists as Global Variable in Python

The global keyword holds a lot of significance in Python and is utilized to manipulate a data structure or a variable outside the scope that it is originally declared in.

A global keyword defines a global data structure or a variable while enabling the user to modify it within the local premises of a function.

This tutorial demonstrates the different ways to define a list as a global variable in Python. First, let us understand the simple rules for using the global keyword in Python.

  • Any data structure created inside a function is local, and its scope is limited to that function only.
  • Any data structure created outside a function is a global data structure by default, and there is no need to precede the given data structure with the global keyword in this case.
  • The global keyword is utilized to manipulate a global data structure inside the scope of a function.
  • When utilized outside a function, the global keyword fails to impact the code in any aspect.

Lists can be treated as a normal variable, and the following methods work efficiently to define a list as a global variable in Python.

Use the global Keyword to Define a List as a Global Variable in Python

As mentioned in the basic rules of the global keyword, it can be utilized inside the function to manipulate the given global data structure inside the scope of a function.

x = []
def tes1():
    global x
    x = [1]
tes1()
print (x)

Output:

[1]

In the above code, the output indicates that the global keyword along with the list successfully defines a list as a global variable. The manipulation of this list is also carried out within the function definition.

We should note that in operations like assignment of the variable, the global keyword needs to be utilized, but it is not necessary to utilize it in the case of generic method calls.

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