NSString & String

1、NSURL-->String
NSString *urlString = url.absoluteString
NSString *str = @"www.weixin.com";
NSURL *url = [];
string -> url
NSURL *URL = [NSURL URLWithString:str];

2、保留两位小数点
String(format: "%.2f", self.resultData[indexPath.row].costPrice)

3、保留小数点--千分位转换
// 保留小数点后两位
let string = "1991.211218"
let string2 = String(formater: "%.2f", string)
print(string2) === 1991.21
// 添加千分位标识符
func separatedFloatStrWith(string: NSString, precision: Int) -> String {
let formatter = NSNumberFormatter()
let value = string.doubleValue
var format = NSMutableString(string: "###,##0")
if precision == 0 {
formatter.positiveFormat = format as String
return formatter.stringFromNumber(NSNumber(double: value))!
}else{
format = NSMutableString(string: "###,##0.")
for _ in 1...precision {
format.appendFormat("0")
}
formatter.positiveFormat = format as String
return formatter.stringFromNumer(NSNumber(double: value))!
}
}

4、拼接
NSString *newString = [NSString stringWithFormat:@"%@%@", tempA, tempB];

5、字符转int
int intString = [newString intValue];
int转字符
NSString *stringInt = [NSString stringWithFormat:@"%d", intString];

7、字符转float
float floatString = [newString floatValue];
float转字符
NSString *stringFloat = [NSString stringWithFormat:@"%f", intString];

8、set方法
set {
let startIndex = self.startIndex.advancedBy(range.startIndex)
let endIndex = self.startIndex.advancedBy(range.endIndex)
let strRange = Range(startIndex.. self.replaceRange(strRange, with: newValue)
}

9、
Swift学习之转义字符