swift中NSString、NSIntger、int、floa

//创建一个String类型对象

var testString = "11.12"

//string转Float

let testFloat = Float(testString)

//String转Int

let testInt = Int(testFloat!)

//Int转String

testString = String(format: "%d",testInt!)

//Float转String

testString = String(format: "%f",testFloat!)