如何在iOS中添加有序缩写格式到日期，例如“th”，“st”

Question

我有以下代码将日期和时间格式化为字符串，如：

2013年10月25日星期一 - 14:56:34

NSDate *today = [[NSDate alloc] init];
dateFormatter = [[NSDateFormatter alloc] init];
[self.dateFormatter setDateFormat:@"EEEE, MMMM dd YYYY - HH:mm:ss"];

NSString *currentTime = [self.dateFormatter stringFromDate: today];
self.timerLabel.text = currentTime.uppercaseString;

效果很好。但是我如何把＃34; th＆＃34;或者＆＃34; rd＆＃34;或者＆＃34; st＆＃34;适当的日期，即上例中的25之后？

Answer 1

NSDateFormatter *format = [[NSDateFormatter alloc] init];
[format setDateFormat:@"MMMM dd"];

NSDate *now = [[NSDate alloc] init];

NSString *dateString = [format stringFromDate:[now dateByAddingTimeInterval:(-60*60*24*10)]];
NSMutableString *tempDate = [[NSMutableString alloc]initWithString:dateString];
int day = [[tempDate substringFromIndex:[tempDate length]-2] intValue];
switch (day) {
    case 1:
    **case 21:
    case 31:**
        [tempDate appendString:@"st"];
        break;
    case 2:
    **case 22:**
        [tempDate appendString:@"nd"];
        break;
    case 3:
    **case 23:**
        [tempDate appendString:@"rd"];
        break;
    default:
        [tempDate appendString:@"th"];
        break;
}
NSLog(@"%@",tempDate);