Iterating over Arrays

Let's see how we can iterate over C# arrays.

But first, we need to look at the Length property.

Length property

You can find how many items are in an array by accessing its Length property:

var fruits = new string[] { "watermelon", "peach", "lemon" };
var length = fruits.Length;
Console.WriteLine(length); // 3

Count method

The array exposes the Count() method as well, but the Length property is faster, so consider using it over the method.

Iteration

We can use the for loop to iterate, or we can just use foreach.

for loop

using the for loop:

for (int i = 0; i < fruits.Length; i++)
{
    Console.WriteLine(fruits[i]);
}

foreach loop

using the foreach loop:

foreach (var fruit in fruits)
{
    Console.WriteLine(fruit);
}

foreach

You can iterate through arrays using foreach because they implement the IEnumerable interface.

When we execute any of these, we get this result:

watermelon
peach
lemon

Press enter to stop execution.

Pretty nice 😃

Michelle nice

Giphy

Loops

My reccomendation is to use foreach over for when looping, but this depends on the scenario: if you need to use the index somehow, then you should use the for loop, if it's just a simple looping through the items, then use foreach. 👍

Nulls

Let's try removing the last two items:

var fruits = new string[] { "watermelon" };

If we run now our code, you can see that we still have

the watermelon 🍉;
and some empty lines with no values.

watermelon



Press enter to stop execution.

Default values

Well, in fact these are not empty. There is a difference between null and empty (coming soon).

In essence, when you don't assign a value to a position in the array, that position gets the default value of the type of the array (in our case it gets null because the type of the array is string and the default value of string is null).

Let's try checking for null values to see if these are indeed null:

foreach (var fruit in fruits)
{
    if (fruit == null)
        Console.WriteLine("This was null");
    else 
        Console.WriteLine(fruit);
}

And we can see in the result that we have indeed null values:

watermelon
This was null
This was null

Press enter to stop execution.

TIP

The compiler just doesn't print null to the console. It prints nothing, but we as programmers know that those are in fact null values. 😆

Wrapping up

Amazing, you know about default values and looping over arrays.

I am going to cover all the other default values soon, so keep an eye on my channel and on this website 🙃

# Iterating over Arrays

# Length property

# Iteration

# for loop

# foreach loop

# Nulls