Safe element of array access

Question

What is the safe method to access an array element, without throwing IndexOutOfRangeException, something like TryParse, TryRead, using extension methods or LINQ?

Answer 1

You could use the following extension method.

public static bool TryGetElement<T>(this T[] array, int index, out T element) {
  if ( index < array.Length ) {
    element = array[index];
    return true;
  }
  element = default(T);
  return false;
}

Example:

int[] array = GetSomeArray();
int value;
if ( array.TryGetElement(5, out value) ) { 
  ...
}

Answer 2

Use the System.Linq ElementAtOrDefault method. It handles an out-of-range access without throwing an exception. It returns a default value in the case of an invalid index.

int[] array = { 4, 5, 6 };
int a = array.ElementAtOrDefault(0);    // output: 4
int b = array.ElementAtOrDefault(1);    // output: 5
int c = array.ElementAtOrDefault(-1);   // output: 0
int d = array.ElementAtOrDefault(1000); // output: 0

Answer 3

If you want to loop through the elements in the array safely, just use an enumerator:

foreach (int item in theArray) {
   // use the item variable to access the element
}