Published by Arunprasadh C on 21 Apr 2022 • Last Updated on 28 Apr 2022

Data Types available in Swift

In any programming language, Data Types are quite important as they decide the amount of memory to be allocated to a variable/constant. Swift supports the following Built-in Data Types :

• Int or UInt − This is used for whole numbers. More specifically, you can use Int32, Int64 to define 32 or 64 bit signed integer, whereas UInt32 or UInt64 to define 32 or 64 bit unsigned integer variables. For example, 42 and -23. On 32-bit Platforms, Int or UInt will automatically refer to Int32 or UInt32 respectively. Similar reference is done on 64-bit Platforms. Even 8-bit and 16-bit versions of Int/UInt types are available.
• Float − This is used to represent a 32-bit floating-point number and numbers with smaller decimal points. For example, 3.14159, 0.1, and -273.158.
• Double − This is used to represent a 64-bit floating-point number and used when floating-point values must be very large. For example, 3.14159874897578.
• Bool − This represents a Boolean value which is either true or false.
• String − This is an ordered collection of characters. For example, “Hello, World!”.
• Character − This is a single-character string literal. For example, “C”.
• Optional − This represents a variable that can hold either a value or no value.
• Tuple − This is used to group multiple values in single Compound Value.

Now that we have seen the various Data types, let’s see how much space is allocated for variables of each Data Type and the range of values that can be represented using each data type:

Data Type	Space required for a single Variable	Range of values that can be represented
Int8	1 byte	-128 to 127
UInt8	1 byte	0 to 255
Int16	2 bytes	-32768 to 32767
UInt16	2 bytes	0 to 65535
Int32	4 bytes	-2147483648 to 2147483647
UInt32	4 bytes	0 to 4294967295
Int64	8 bytes	-9223372036854775808 to 9223372036854775807
UInt64	8 bytes	0 to 18446744073709551615
Float	4 bytes	1.2E-38 to 3.4E+38 (~6 digits)
Double	8 bytes	2.3E-308 to 1.7E+308 (~15 digits)
Bool	1 byte	Range not Applicable. Can hold either true or false

Type Aliases

Swift allows us to define new names for existing Data Types. These new names can be used as actual Data Type Names. Type Aliases can be defined using the following Syntax:

typealias newName = Type

Example :

typealias Number = Int
var x: Number = 56

Type Safety

Swift is a type-safe language, which means that we can’t assign a literal or object of a different type to a variable/constant of some other type. For example, the following code will produce the error error: cannot assign value of type 'String' to type 'Int' at Compile time :

var a: Int = 5
a = "Hello"

Type Inference

Swift can infer the Data Type from the type of literal/object assigned to a variable/constant.

Example :

var a = 4 // Inferred as Int
var b = "Hello World" // Inferred as String

Now that we have seen basically about Data types in Swift, we can move on to see in Detail about Characters and Strings in Swift.

← Back to Index
← Introduction to Swift Characters and Strings →