iOS 四舍五入求整数

在项目中一些数字的显示难免会取整显示，四舍五入后保留一位小数，然而当最后一位是0的时候，要省略掉这个‘.0’，下面方法利用roundf函数对小数点最后一位做判断是否是0

func qiuZhengshu(_ string:String)->String {

var newN = ""

if string.floatValue() > 10000 {

let number = string.floatValue() / 10000

let lastStr = formatFloat(number)

newN = "\(lastStr)" + "万"

}else if string.floatValue() > 1000 {

let number = string.floatValue() / 1000

let lastStr = formatFloat(number)

newN = "\(lastStr)" + "千"

}else {

newN = string + ""

}

return newN

}

func formatFloat(_ f:Float)->NSString {

let str = NSString(format: "%.1f", f)

let number = str.floatValue

let i = roundf(number)

if i == number {

return NSString(format: "%.0f", number)

}else {

return NSString(format: "%.1f", number)

}

}