Using Array.getInt(Object array, int index) vs Array[]

Question

I'm trying to retrieve the item at the specified index in an array as shown in the body of the forloop.

public int arrayCount9(int[] nums) {
    int count = 0;

    for (int i = 0; i < nums.length; i ++) {
        if (Array.get(nums, i) == 9) {
            count ++;
        }
    }    
    return count;
}

However, the correct code in this problem is actually this:

public int arrayCount9(int[] nums) {
    int count = 0;

    for (int i = 0; i < nums.length; i ++) {
        if (nums[i] == 9) {
            count ++;
        }
    }
    return count;
}

Is there a difference between Array.get(nums, i) == 9) and (nums[i] == 9)? The documentation for get(Object array,int index) seems suitable for this problem. In addition, I've actually never encountered (nums[i] == 9) before so if you could explain that code as well, much appreciated!

I didn't even know this class Array exists. What the heck is the purpose of it? — akuzminykh
– akuzminykh, Commented Jun 19, 2020 at 22:26
@akuzminykh To dynamically create arrays from Class objects? I have to agree that most of the methods seem useless — user
– user, Commented Jun 19, 2020 at 22:28
The get method works with arrays of Objects. Use getInt instead if you have to. However, I don't understand why you simply can't use the second approach with nums[i] — user
– user, Commented Jun 19, 2020 at 22:31
I will use the second approach as it's the only one working. Just wanted to know the difference between the two. Thanks for your help guys! — HarderDatty
– HarderDatty, Commented Jun 19, 2020 at 22:40
Array is the class you'd use when working with the Reflection API and don't want to cast. — Felix
– Felix, Commented Jun 19, 2020 at 22:52

EKW · Accepted Answer · 2020-12-30 01:39:51Z

2

As far as I can tell from the documentation, the most important difference between the two is that Array.get(myArray, myIndex) will return a raw Object, whereas myArray[myIndex] will return a value of the type that myArray stores.

For example, if you have an array of Strings named myStringArray, Array.get(myStringArray, 4) will give you a nondescript Object value, whereas myStringArray[4] will give you a String value.

In general, people tend to use the myArray[myIndex] syntax unless they have a compelling reason not to. It essentially means "get the item in the array named myArray at index myIndex."

edited Dec 30, 2020 at 1:39

answered Jun 19, 2020 at 22:43

EKW

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1 Comment

HarderDatty Over a year ago

Relatively new to java so unsure what's the conventions are but I'll be using myArray[myIndex] from now on. It seems more intuitive anyways. thanks a bunch EKW.

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