For-Each Loop

The last type of loop we want to have a look at is the for-each loop in Java, for-each loops are used to iterate over Arrays or Collections and provide a more concise and readable way of accessing the elements of these data structures.

Traditional for Loop Example

First, let’s look at a traditional for loop used to iterate over an array:

String[] cars = {"Nissan", "Mazda", "Ford"};
for (int i = 0; i < cars.length; i++) {
  System.out.println(cars[i]);
}

In the above code:

• The loop runs for each index of the cars array, from i = 0 to i < cars.length.
• In each iteration, the value at the current index (cars[i]) is printed. For example, when i = 0, cars[0] will be "Nissan", and the loop will continue printing each car name in the array.
• The loop stops when it reaches the last element of the array, ensuring that it doesn’t attempt to access an invalid index.

For-Each Loop

Now, let’s have a look at the for-each loop, which is a simplified way to iterate over arrays and collections:

String[] cars = {"Nissan", "Mazda", "Ford"};
for (String car : cars){
  System.out.println(car)
}

In the above code:

• We no longer need to declare the bounds of our loop as the language and syntax is written to know that we want each car from our pool of cars to return
• Will return the exact same results on our first loop

Limitations

A for-each loop does have its limitations

• Forward-Only Iteration: The for-each loop is designed to iterate over the collection from the first element to the last. It cannot iterate backward like a traditional for loop can (i.e., from the end to the beginning).

• No Access to the Index: In a for-each loop, you don’t have direct access to the index of the current element. This means you can’t reference the position of an element, which might be necessary if you need to perform an operation based on the index (e.g., modifying an array or collection at a specific position).
• No Modification of Collection Elements: Since we don’t have access to the index, it’s also important to note that you cannot modify the elements of an array or collection in place in a for-each loop. You can only access their values.