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In the realm of programming, variables stand as indispensable tools, serving as placeholders for the storage and manipulation of data. Each variable possesses a name, a data type, and a value, allowing programmers to encapsulate and work with diverse information types.

There is no command in Python for setting up a variable. Once you assigned a value  to the variable for first time, it is formed.

age = 25
name = "John"

Here, age and name are variables storing an integer and a string, respectively. You can use these variables throughout your program, and their values can change as needed.

In  Python, where variables dynamically adapt, enabling developers to alter their types after initial assignment, as demonstrated by the transformation of a variable from an integer to a string:

X = 25
X = "John

In the example above, x is of type int on the first line, but we transformed it to a string on the second.

Casting further refines variable types, providing explicit control over data representations:

X = str(3)  
y = int(3)

The determination of a variable’s data type involves the use of the type() function:

X = 25
type(x);

Guidelines for Python variables naming foster clarity and consistency in code:

• Initiate a variable name with an underscore or a letter.
• Preclude the commencement of a variable name with a numeral.
• Restrict variable names to alpha-numeric characters and underscores.
• Recognize the case-sensitivity of variable names.
• Steer clear of Python keywords as variable names.

Python introduces a compact syntax for assigning values to multiple variables in a single line:

x, y, z = "Red", "Gray", "Blue"

Furthermore, one can assign the same value to multiple variables in a concise manner:

x = y = z = "Red"

A variable with the same name that is created inside of a function will be local and limited to use within the function. The identically named global variable will stay global and retain its initial value.

x = "Good Morning"

def myfunc():
  x = "Good Afternoon"
 myfunc()

A variable is often local to the function in which it is created, meaning that it can only be used within that function.

The global keyword can be used within a function to create a global variable.

def myfunc():
  global x
  x = "Good Morning"

myfunc()

Reserved words in Python

and, as, assert, break, class, continue, def, del, elif, else, except, exec, finally, for, from, global, if, import, in, is, lambda, not, or, pass, print, raise, return, try, while, with, yield.

Here’s a link to some books that you can read to gain more knowledge. Happy Learning!!