Arraylist - How to Check If an Index Exists

ArrayList - how can I check if an index exists?

The method arrayList.size() returns the number of items in the list - so if the index is greater than or equal to the size(), it doesn't exist.

if(index >= myList.size() || index < 0){
  //index does not exists
}else{
 // index exists
}

How to find if an array index Exists?

Basically I need to check if a String contains 2 indexes

If you are using split() it returns you an array which you can use .length to check the size of the returned tokens:

if(parts.length >= 2)

But that is not gonna tell if the second index is empty, right?

If you are afraid of getting empty string, you can trim() the String first:

String[] parts = datareceived.trim().split("&");

How to detect if an index exists in an array (String[])?

You need to check length of your array, so:

if(fileAndMacro.length > 1)
   macroName = fileAndMacro[1];

By accessing an index that doesn't exist, you would be accessing some other space in memory which does not belong to your created array (actually created in the split() method), that's why you get an exception.

Java: ArrayList: Determine if entry exists by its index

Not at all sure what your question is. You talk about seeing if an entry "exists" but then you talk about Java lacking a remove(Object index) method.

Regarding remove: There's the remove(int) method on the List interface implemented by ArrayList. (Java Lists are indexed by int, not by Object.)

Regarding whether an entry "exists" at a given index, if the list's size() method is greater than the index (and the index is non-negative), then there's an entry at that index:

if (index >= 0 && index < list.size()) {
    // An entry exists; hey, let's remove it
    list.remove(index);
}

How to check if the all the indexes of an ArrayList has no file in them?

Or make it a method:

    public boolean fileFound(List<String> logopaths) {
        boolean atLeastOneFileExists = false;
        for (int i = 0; i < logopaths.size() && !atLeastOneFileExists; i++) {
            String s = logopaths.get(i);
            File file = new File(s);
            atLeastOneFileExists = file.exists();
        }
        return atLeastOneFileExists;
    }

Check If Index Exists in Array D

Firstly, never ever check if an index is within an array by dereferencing it.

bool check(int[] arr, size_t index)
{
    return index < arr.length;
}

unittest {
    assert(!check([], 0));
    assert(!check([1], 1));
    assert(check([1, 2], 1));
    auto testArray = new int[1024];
    //testArray[testArray.length] = 1; // this throws, so check should return false
    assert(!check(testArray, testArray.length));
}

enjoy

Flutter - Check if an index exists in List

You can convert the List to a Map and check the keys:

List<int> numbers = [1, 2, 3, 4, 5,];

//Check if index 7 is valid
if (numbers.asMap().containsKey(7)) {
  print('Exists');
} else {
  print('Doesn\'t exist');
}

//[EDIT] Check if item at index 4 exists and is 5
if (numbers.asMap()[4] == 5) {
  print("Index 4 = 5");
} else {
  print("Index 4 != 5");
}