In my last post, I talked about comparisons using equality. Today, I want to talk about inequality. There might be situations where you want to check to make sure two items are NOT equal to each other. So how would we do that? We would use the not equal operator (!=). The exclamation point is known commonly as the not operator. There are various situations to use the exclamation point. Here is an example of not equal…
[code lang=”js”]
// Not equal example
var yourNum = 5;
var myNum = 3;
if(yourNum != myNum){
// Do something as a result of not being equal
}
[/code]
The aforementioned condition statement would return true because the variables yourNum (5) is not equal to myNum (3).
In my previous post, I also spoke of absolute comparisons….meaning comparing values and type with the triple equals signs (===). We can do the same thing with not equals by adding an equals sing…!==. So using this (!==) is asking if it is absolutely not equal. First lets look at an example that uses a single equal sing…
[code lang=”js”]
// Not equal example just comparing values
var firstNum = 5;
var secondNum = "5";
if(firstNum != secondNum){
// Do something
}
[/code]
In the above code, the ‘do something’ section within the curly braces would not run because the condition statement would return false. This is because the value of firstNum (5) is equal to the value of secondNum (“5″). Now let’s add an equal sign…
[code lang=”js”]
// Not equal example just comparing values
var firstNum = 5;
var secondNum = "5";
if(firstNum !== secondNum){
// Do something
}
[/code]
This code would return true because firstNum is not absolutely equal to secondNum. They are equal in value (5 == 5), but not in type (integer != string).
Rule of thumb…use absolutes as often as possible…so add the extra equal sign.
Happy Coding!
Clay Hess
