Boolean logic is a key concept in any programming language, whether you’re creating a video game with C++, developing the next best app in Swift, searching through relational databases in SQL, or working with big data in Python. In this article, we’ll cover what Boolean logic is, how it works, and how to build your own Boolean expressions.
Boolean logic is a type of algebra in which results are calculated as either TRUE or FALSE (known as truth values or truth variables). Instead of using arithmetic operators like addition, subtraction, and multiplication, Boolean logic utilizes three basic logical operators: AND, OR, and NOT.
Behind Boolean logic are two very simple words: TRUE and FALSE.
Note that a Boolean TRUE or FALSE is very different from typing the strings “True” and “False” into your code. In fact, programming languages put these two Boolean values into their own object type separate from integers, strings, and floating-point numbers. But while there can be practically infinite possibilities for a numerical or string value in programming, there are only two possible Boolean values: TRUE and FALSE.
How does this work? Boolean logic looks at a reported relationship between things and determines whether the relationship holds. For example, let’s take the equation:
Here, we have two parts, 2 + 2 and 4, and we’re reporting that those two parts are equal to each other. Is that right? Yes it is, so the Boolean result of this would be TRUE. In this example, the combination of the two parts 2 + 2 and 4, together with the relationship (= equals), is called a Boolean expression.
Let’s look at another Boolean expression:
Here, we’re reporting that 4 subtracted from 10 is the same as 5. Is that right? Of course not, and that’s why this Boolean expression would return a value of FALSE.