将字符串"12345"转换成"1-2-3-4-5"
NSString *originalString = @"12345";
NSMutableArray *pointsArray = [[NSMutableArray alloc]init];
for (int i = 0; i < originalString.length; i ++)
{
NSString *tempString = [originalString substringWithRange:NSMakeRange(i, 1)];//NSMakeRange参数意义:从第i位开始截取,截取长度为1
[pointsArray addObject:tempString];
}
NSString *newString = [pointsArray componentsJoinedByString:@"-"];