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JavaScript

Posted by Roland O'Donnell
Roland O'Donnell
5,667 Points

why won't this or any slight variance of this work? I'm bedazzled

var x = [1,2];

var y = [1,2];

if (x[0] && x[1] == y[0] && y[1] ) {

print("You have Won LOTTO!!!");

} else {

print("waste of money idiot!!");

}

Roland O'Donnell
Roland O'Donnell
5,667 Points

all i want to do is know how to compare two arrays to see if they are the same..thanks

2 Answers

Thomas Nilsen
Thomas Nilsen
14,957 Points

There are multiple ways you can check if two arrays are equal.

First, you can convert both of them to a string, and then compare:

console.log(x.toString() === y.toString()); //true

or you can make a function where you loop through the array and compare each element to each other:

function arraysEqual(arr1, arr2) {
    if(arr1.length !== arr2.length)
        return false;
    for(var i = arr1.length; i--;) {
        if(arr1[i] !== arr2[i])
            return false;
    }

    return true;
}

console.log(arraysEqual(x, y)); //true

Or, to do what you (almost) did:

if(x[0] === y[0] && x[1] === y[1]) {
    console.log("You have Won LOTTO!!!");    //This will print
} else {
    console.log("waste of money idiot!!");
}
Jason Anello
Jason Anello
Courses Plus Student 94,610 Points

You're probably going to be better off with the function solution and examining each element.

The .toString() method is going to lead to incorrect results for certain arrays.

Consider the following 2 examples:

console.log(["cat,dog"].toString() === ["cat", "dog"].toString()); // true
console.log([1, 2].toString() === ["1", "2"].toString()); // true

They are both true even though the arrays are not the same.

Roland O'Donnell
Roland O'Donnell
5,667 Points

thank you, just so understand something else, whenever a function hits a return statement it exits the function? is that correct? so if the arrays are not the same length it will return false and exits the function with out ever running the rest of the function?

thanks again again for your help!

Thomas Nilsen
Thomas Nilsen
14,957 Points
Thomas Nilsen
Thomas Nilsen
14,957 Points

That is correct :) If the arrays is not of equal length - then we know for sure that the arrays cannot be equal and we end the function there.