Swift offers a rich collection of built-in and user-defined data types.
There are six basic data types in Swift: string, character, integer, float, double, and boolean. These data types are common in most programming languages. Each data type is discussed below.
StringA String is a data type used to store a collection of characters. So, a series of characters represent a string. Strings are used to represent textual data displayed in an app.
When writing a String, it must be wrapped in quotes to be considered valid. We use the String keyword to create string-type variables. The example below demonstrates how to create a string-type variable.
let text: String = "Hello, world"print(text)
Hello, world
IntegerInteger, also represented as Int, is a data type used to perform mathematical operations such as addition, subtraction, and multiplication.
Integer is also used to represent whole numbers with no fractional components. We use the Int keyword to create integer-type variables. An example is shown below.
let digit: Int = 5print(digit)
Depending on the platform type, Swift programming provides different variants of
Integerthat have different sizes.
5
CharacterCharacters are used to store a single character string, whether it is a literal, emoji, or a language other than English. If more than one character is assigned to a variable of type Character, an error message is thrown.
We use the Character keyword to create character-type variables. An example is shown below.
let alphabet: Character = "a"print(alphabet)
a
FloatFloat or Floating-point number is a data type used to represent whole numbers with a fractional component. Floats are also used to perform various mathematical operations and store numbers with up to six decimal places.
We use the Float keyword to create float-type variables. An example is shown below.
let sampleFloat: Float = 3.333print(sampleFloat)
3.333
DoubleThe Double data type is similar to Float and is used to represent whole numbers with a fractional component. Double differs by storing numbers with up to 15 decimal places.
We use the Double keyword to create double-type variables. An example is shown below.
let sampleDouble: Double = 13.3107967012433print(sampleDouble)
13.3107967012433
Booleanboolean or Bool is a data type used to represent logical entities. We use boolean to determine if logic is true or false. Boolean is usually used with if-else statements.
We use the Bool keyword to create boolean-type variables.
let checkPassed: Bool = trueprint(checkPassed)
true