Is there a way to return true or false without using an 'if' statement as shown in the first example?
First Example:
function isEven(){
if(num % 2 === 0){
return true;
} else {
return false;
}
}
While this code works, my teacher showed me a shorter alternative (Example 2):
function isEven(){
return num % 2 === 0
}
The function allows for a variety of return values based on the input parameter. Take a look at the example provided below for further clarification.
function myFunction(val) {
console.log(test(val))
}
function test(val){
if(val==1) return 'testing';
if(val == 2) return true;
if(val == 3) return 1>2;
if(val == 4) return 2%3 == 0;
}<button onclick="myFunction(1)">Test1</button>
<button onclick="myFunction(2)">Test2</button>
<button onclick="myFunction(3)">Test3</button>
<button onclick="myFunction(4)">Test4</button>I'm not providing a definitive answer, just offering some guidance, so please refrain from upvoting!
One approach to grasping the fundamentals of programming is by relating them to everyday scenarios. Here's an example:
Imagine you're chatting with a friend named Bob who runs an ice cream shop during the summer. When you ask him for ice cream, he responds:
"If there is any ice cream left, I can give you some; otherwise, I cannot."
function canIGetIceCream() {
if (isIceCreamLeft) {
return true;
} else {
return false;
}
}
Alternatively, Bob could simplify his response while retaining the same meaning:
"It depends on the amount of ice cream left."
function canIGetIceCream() {
return isIceCreamLeft;
}
Booleans are simply values, similar to numbers or strings. In the initial example, if isIceCreamLeft is true, it will trigger the first condition and ultimately return true. Conversely, if it is false, it will return false. Alternatively, in the second scenario, you directly return the boolean value without additional logic.
When you use an if statement, you are not really asking a question. The if statement simply determines whether the expression within the parentheses ( ) is either considered to be true or false. For instance, just like how adding 1 + 2 gives 3, comparing 3 === 2 will result in false. Essentially, it is like solving a math problem with a definite answer. So when your computer calculates:
num % 2 === 0
It computes num % 2 and then checks if it equals 0, leading to either true or false. Both of these outcomes are boolean values, similar to the first example. Therefore, in essence, the purpose of the initial example is to ascertain whether the expression is true or false before returning that precise value. It can be demonstrated as follows:
var num = 2;
if(num % 2 === 0){
return true;
}
Ultimately, after evaluation, the code translates to:
if(true){
return true;
}
From this perspective, wouldn't it be more efficient to skip the if statement altogether and directly return the result of num % 2 === 0?
If you want to grasp the concept here, focus on how operators function.
Operators work on operands. When an operator is combined with one or more operands, it forms an expression that needs to be evaluated.
The return statement takes an expression and gives back the value produced by evaluating that expression. For instance, 1 + 2 results in 3.
Comparison and logical operators, such as ==, <, and &&, typically result in either true or false. In simple terms, true && false leads to false, while 1 == 1 evaluates to true.
Hence, return num % 2 == 0 is perfectly acceptable because when this code snippet runs, num % 2 gets assessed first before the entire expression is determined to be either true or false. Essentially, you can imagine the full statement simplifying down to
return true;
or
return false;
once the evaluation of the expression is completed.
Below is an assessment for you:
num % 2 === 0
This particular code snippet verifies whether the remainder of dividing 'num' by 2 (num % 2) equals 0. The result can be either true or false, depending on the outcome.
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