Swift vs Groovy – Types

Getting started Swift types

Int Integer, whole number that does not containing any floating point information.
Float 32bit number with floating point information
Double 64bit number with floating point information
Bool true or false
String represents text
Character Single unicode character

There are more types but those are the most common in Swift.

Type Naming

Swift Types and the types you defined should be UpperCamelCase. Same in Groovy. However, in Groovy we have access to java primitives short, int , long, float, double, byte, char, boolean etc. Those are lowercase.

Type inference

If we don’t explicitly defined a type both Swift and Groovy will try to infer it.


let i = 42 // Int
let d = 42.5 // Double


def i = 42 // java.lang.Integer
def d = 42.5 // java.math.BigDecimal

Define type explicitly

let i: Int = 42
let d: Double = 42.5


Integer i = 42
Double d = 42.5

Type conversion


let d: Double = 42.5
let i: Int = Int(d) // 42


final Double d = 42.5 // java.lang.Double
final Integer i = (Integer)42.5 // 42 java.lang.Integer
final Integer x = 42.5 as Integer // 42 java.lang.Integer

as keyword in Swift

If the default inferred type is not what you are looking for, you convert value to type with the as keyword

let x = 42 as Double

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