Important Rules while Creating Variables

Programming languages understand instructions only if they are given in a specified format (or syntax). When creating variables, we need to be careful of these rules, or the variables will not be created properly, and the program may give errors.

• Variable names can be created using alphabetical letters (a-z and A-Z), digits (0-9), or underscore symbol (_). Special symbols are not allowed. For example, abc&def is an invalid variable name.
• Variable names can begin with the underscore symbol or alphabetical letters only, not digits. For example, 123abc is an invalid variable name and will give you an error.
• Variables in Python are case-sensitive. This means that if we declare two variables score and Score with different values assigned to them, then they are two different variables (not the same variable!).
• Every programming language has certain keywords, that define in-built functionality in the language. These should not be used as variable names. Since it has a different meaning in the language, declaring variables with already existing keyword names will cause an error. These keywords will be highlighted with a different color whenever you type them, so it is easy for you to distinguish. For example, and is a keyword in Python, hence declaring a variable with that name would raise an error.
• In Python, it is important to assign a value to a variable. If you only define the variable without assigning it a value, it will produce an error.

Now that we know how to create variables, let's see if we understood them properly.