你如何在swift中使用解析字符串？

Question

這里有一個問題，如果我使用解析字符串作為計算器程序的結果，例如，

4.5 * 5.0 = 22.5 

如何在這里使用拆分從結果中刪除小數部分？

Answer 1

使用modf從結果中extract decimal part 。

Objective-C ：

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

斯威夫特 ：

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

---

只需要浮動雙倍的整數部分

只需要double integer數值

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

只想float integer數值

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

Answer 2

假設您只使用字符串：

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
}