Swift Array to String

To convert an array to string in Swift, call Array.joined() function.

For instance, let’s combine a list of names into a string that separates the names with a space:

let names = ["Alice", "Bob", "Charlie"]
let nameString = names.joined(separator: " ")

print(nameString)

Output:

Alice Bob Charlie

1. The Array.joined() Function in Swift

The Array.joined() function in Swift can be called to create a string based on the elements of the array.

The syntax is:

Array.joined(separator:)

Where the separator is an optional argument. If specified, it defines the separator to put between each element in the array in the resulting string.

For instance, let’s combine a list of names without a separator:

let names = ["Alice", "Bob", "Charlie"]
let nameString = names.joined()

print(nameString)

Output:

AliceBobCharlie

Now, let’s separate these names by a comma:

let names = ["Alice", "Bob", "Charlie"]
let nameString = names.joined(separator: ",")

print(nameString)

Output:

Alice,Bob,Charlie

Notice that the separator does not need to be a single character.

For example, let’s separate the names with three dashes:

let names = ["Alice", "Bob", "Charlie"]
let nameString = names.joined(separator: "---")

print(nameString)

Output:

Alice---Bob---Charlie

Now that you understand how the Array.joined() method works, let’s take a look at some common tasks you can solve using it.

2. How to Create a String from an Array of Characters

To create a string from a list of singular characters, use the Array.joined() function just like you would use it on an array of strings.

Let’s see examples of separating the characters by a comma and not separating the characters at all.

2.1. Separated by a Comma

let names = ["A", "B", "C"]
let nameString = names.joined(separator: ",")

print(nameString)

Output:

A,B,C

2.2. Non-separated

let names = ["A", "B", "C"]
let nameString = names.joined()

print(nameString)

Output:

ABC

3. How to Create a String from Numbers

If you have an array of numbers, you cannot directly call Array.joined() on it to create a string. Instead, you need to convert the array of numbers to an array of strings.

For example:

let nums = [1.0, 2.0, 3.0]
let numsString = nums.map { String($0) }.joined(separator: ", ")

print(numsString)

Output:

1.0, 2.0, 3.0

In case you are wondering what the $0 does, check out this article.

4. Conclusion

Today you learned how to use the Array.joined() function in Swift.

To recap, you can combine an array of strings to a string with the Array.joined() function. If you want to separate the strings, specify a separator in the call.

names.joined(separator: " ")

Thanks for reading.

5. Further Reading

50 Swift Interview Questions

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