Swift array: The simple guide you need to know

As you can see, Swift includes a lot of things that we need to explore to understand all about it. And, one of them is Swift Array. Coming to this topic, ArrowHiTech will recommend for you the simple guide you need to know to make it as easy as possible. Let’s read with us now!

Swift array

What does “Array” mean?

Firstly, an array is a container that allows you to save a big amount of multiple data (values) of a data type in an ordered list. Then, you can sort and collect the elements in the same order according to the items you determined in the array. An array can contain values of any data form, such as: Int, String, and so on.

Swift array

The simple guide to work with Swift array

In order to create an empty Swift array, you can specify the data type inside square brackets. However, you must remember to follow the type inside square brackets [].. If you don’t do that, Swift will see it as a normal data type. Hence, you can save only a single value in it.

Make an empty Swift array 

For example, if you want to format an empty array, let’s do like below:

empty array

As soon as you run the program, the first finding will be:

empty Swift array

Another way to declare an empty array is: 


Create an Swift array with some values


Doing follow the image above and the result you achieve is:

Swift array values

In the above program, we don’t need to specify the type explicitly yet still declare a constant someIntArr that can save an array of Integer. Additionally, we have initialized array with 1, 2, 3, 4, 5, 6, 7, 8, 9 values.

Accessing elements of a Swift array


The outcome of this program is:

elements of Swift array

Not only that, you can get access to elements by using for-in loops. Explore more here.

Way to modify/add array elements in Swift

Just by using subscript syntax and assignment operator, you’ve done. 

Swift array

As soon as you run this program above, you will get the result:

modify array

Modify an entire Swift array

modify of Swift array

After running this program, the output will appear:


Adding a new element in an array

You can use subscript syntax in order to add a new element in an array. 

Swift array

This program will show the result:

Swift array

While assigning a new element to the Swift array intArr in the above program, an error will occur. This is due to the fact that intArr has not allocated additional memory for index 4 and thus is unable to store the provided value. We use the array’s append()method to correctly insert a new element into an array.

Suggest some helpful built in Array functions & properties


We can determine if an array is empty or not thanks to isEmpty. If an array does not contain any values, it comes to true; otherwise, it returns false. 


The output will be: 

output of isEmpty


If you want to access the first element of an array, this property will help you. 


You have to write code as above program and the output returned will be:

First Swift array

Similarly, with the final element of an array, in order to access it, you must use last property. 


Right from its name, this function allows us to insert elements at a specific index of the Swift array. 

Insert Swift array

The above image illustrates how this function works and the below one is the output it shows. 

By contract, in order to remove any element at specified index, you have to use remove property. 


This function extracts and returns the specified value from the array at the specified location. 


According to the above program, the result will be:

Remove - Swift array


This function reverses the order of the array’s elements. And its work is:


Following that, the finding will be:

result Swift array


Total number of elements will be shown in an array thanks to this property. 


Practice according to this above program and you will see the output:

output code

Important thing

If you use Swift’s subscript syntax to access elements of an array, make sure the value is in the index, or you’ll get a runtime error. Let’s take a look at an instance:

Important thing of Swift array

As soon as we write like this, the output will be:


The index -1 in the preceding program has no meaning. As a result, attempting to reach the value in the index would result in a runtime crash.

In order to stop this, looking for the index of the element you are trying to remove is the most essential thing. 

ArrowHiTech Swift

Removing by this way and you will see the output: 

Swift array ArrowHiTech

In conclusion

Above all, ArrowHiTech believes through this blog, you can have an overview of Swift array and can use it effortlessly with some simple guides we recommend. However, in case you get any struggle with the Swift array, you can ask us for help. With a lot of experience in Web/mobile app development, we surely never make you disappointed.