Purpose of a variable
In programming, a variable is a storage location that holds a value. In Python, variables are used to store values of different data types, such as integers, floating point numbers, and strings. The purpose of a variable is to allow a programmer to store and manipulate data in a program.
Create a Variable
To create a variable in Python, you simply need to assign a value to a name. For example:
x = 10 y = "Hello, World!" z = 3.14
In the above code, we have created three variables: x, y, and z. x is an integer with a value of 10, y is a string with a value of "Hello, World!", and z is a floating point number with a value of 3.14.
Variable Naming Convention
There are a few rules to follow when naming variables in Python:
- Variable names can only contain letters, numbers, and underscores.
- Variable names cannot begin with a number.
- Variable names are case-sensitive.
Here are some examples of valid and invalid variable names in Python:
# Valid variable names my_variable x1 _private # Invalid variable names 1x # cannot begin with a number my-variable # cannot contain hyphens
In Python, variable names are case-sensitive. This means that the variables x and X are considered to be different variables. For example:
x = 10 X = 20 print(x) # prints 10 print(X) # prints 20
It is a good practice to use lowercase letters for your variables, but you can use uppercase letters as well if it makes sense for your code. Just be aware that Python treats them as different variables.