如何在swift中使用解析字符串？

Question

一個問題到我這裏來，如果我使用解析字符串比如計算器程序的結果，

4.5 * 5.0 = 22.5 

怎麼用分裂這裏出發小數部分的結果呢？

Answer 1

使用modf到extractdecimalpart從結果。

Objective-C的：

double integral = 22.5; 
double fractional = modf(integral, &integral); 
NSLog(@"%f",fractional); 

夫特：

var integral:Double = 22.5; 
let fractional:Double = modf(integral,&integral); 
println(fractional); 

---

只想整數部分從雙浮子

想從double只有integer值，那麼

let integerValue:Int = Int(integral) 
println(integerValue) 

想從float只有integer值，那麼

let integerValue:Float = Float(integral) 
println(integerValue) 

Answer 2

假設你只有字符串：

var str = "4.5 * 5.0 = 22.5 " 

// Trim your string in order to remove whitespaces at start and end if there is any. 
var trimmedStr = str.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet()) 
// Split the string by " " (whitespace) 
var splitStr = trimmedStr.componentsSeparatedByString(" ") 

// If the split was successful, retrieve the last past (your number result) 
var lastPart = "" 
if let result = splitStr.last { 
    lastPart = result 
} 

// Since it's a XX.X number, split it again by "." (point) 
var splitLastPart = lastPart.componentsSeparatedByString(".") 

// If the split was successful, retrieve the last past (your number decimal part) 
var decimal = "" 
if let result = splitLastPart.last { 
    decimal = result 
}