Introduction to Python Variables

A variable is a named location in memory that can be used to store data. In Python, variables are created when they are assigned a value. For example, the following code creates a variable named x and assigns it the value 10:

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x = 10

Once a variable has been created, it can be used to store data. For example, the following code stores the value 20 in the variable y:

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y = 20

Variables can be used to store any type of data, including numbers, strings, lists, and dictionaries.

Variable Names

Variable names in Python can be any length and can consist of letters, numbers, and underscores. However, there are a few rules that must be followed when naming variables:

• Variable names must start with a letter or an underscore.
• Variable names cannot start with a number.
• Variable names cannot contain spaces.
• Variable names cannot contain any special characters, such as !, @, or #.

It is also a good practice to make variable names meaningful. For example, instead of using a variable name like x, you could use a name like product_price. This will make your code more readable and understandable.

Variable Types

In Python, variables can be of different types. The type of a variable determines what type of data it can store. The following table shows some of the most common variable types in Python:

• int(): Converts a string or float to an integer.
• float(): Converts a string or integer to a float.
• str(): Converts an object to a string.
• list(): Converts an iterable object to a list.
• tuple(): Converts an iterable object to a tuple.
• set(): Converts an iterable object to a set.
• dict(): Converts an iterable object to a dictionary.

Variable Scope

The scope of a variable is the part of a program where the variable can be used. There are two types of variable scope in Python: local scope and global scope.

• Local scope refers to the part of a program where a variable is defined. Variables that are defined within a function or a class have local scope.
• Global scope refers to the entire program. Variables that are defined outside of any function or class have global scope.

Variables that are defined in the global scope can be accessed from anywhere in the program. However, variables that are defined in a local scope can only be accessed within that local scope.

Variable Assignment

Variables can be assigned values using the equal sign (=). For example, the following code assigns the value 10 to the variable x:

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x = 10

Variables can also be assigned multiple values at once. For example, the following code assigns the values 10, 20, and 30 to the variable y:

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y = (10, 20, 30)

Variable Modification

Once a variable has been assigned a value, it can be modified by assigning it a new value. For example, the following code modifies the value of the variable x to 20:

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x = 20

Variable Deletion

Variables can be deleted using the del keyword. For example, the following code deletes the variable x:

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del x

Conclusion

Variables are an important part of any programming language. In Python, variables are used to store data and to refer to objects. Variables can be of different types, and they can be defined in different scopes. By understanding how variables work, you can write more efficient and readable Python code.