Variable Declaration in Swift -- IOS

//Variable Declaration -

To declare a variable , the data type of the variable is inferred from the value assigned to the variable .

var str = "Hello, playground"

//change the value of the variable 

str = "Hello  Swift"

//Error --- The "str" variable has a datatype of string , and cannot be re-assinged as an Int , float etc..

//You can also explicitly declare the data type in variable 

var name :String = "Hello , Swift"

var age: Int = 45

commonly used data types include String,  Int,  Float,  Double, Bool.  Sample variable declaration for the different data types - 

var S:String = "Swift"

var W: Bool = true

var I: Int = 67

var F: Float = 13.3

var T: Double = 2.2

You can use x.dynamicType to find out the data type of var "X"

let string = "Hello World!”

let array = [“Hello”, “Swift”]

let dictionary = [“dictionary”: 1]

print(string.dynamicType) // "String"

// Get type name as a string

String(string.dynamicType) // "String"

String(array.dynamicType) // "Array<String>"

String(dictionary.dynamicType) // "Dictionary<String, Int>"

// Get full type as a string

String(reflecting: string.dynamicType) // "Swift.String"

String(reflecting: array.dynamicType) // "Swift.Array<Swift.String>"

String(reflecting: dictionary.dynamicType) // "Swift.Dictionary<Swift.String, Swift.Int>"