//设置日期格式
[dateformatter setDateFormat:@"YYYY-MM-dd HH:mm"];
//将日期转换成NSString类型
NSString *string = [dateformatter stringFromDate:date];
NSLog(@"ncurrent = %@",string);
//截取日期substringToIndex
NSString *currentDate = [string substringToIndex:10];
NSLog(@"ncurrentDate = %@",currentDate);
打印结果：
current = 2016-01-1711:12
currentDate = 2016-01-17
2、抽取中间子串-substringWithRange
复制代码//截取月日
NSString *currentMonthAndDate = [string substringWithRange:[NSMakeRange(5, 5)]];
NSLog(@"currentMonthAndDate = %@",currentMonthAndDate);
打印结果：
currentMonthAndDate = 06-27
3、从某一位置开始截取- substringFromIndex
复制代码
//截取时间substringFromIndex
NSString *currentTime = [string substringFromIndex:11];
NSLog(@"ncurrentTime = %@",currentTime);
打印结果：
currentTime = 11:25
四、比较字符串
复制代码NSString *first = @"string";
NSString *second = @"String";
1、判断两个字符串是否相同-isEqualToString方法
复制代码
BOOL isEqual = [first isEqualToString:second];
NSLog(@"first is Equal to second:%@",isEqual);
打印结果：
first is Equal to second:0
2、compare方法比较字符串三个值
复制代码NSOrderedSame//是否相同
NSOrderedAscending//升序，按字母顺序比较，大于为真
NSOrderedDescending//降序，按字母顺序比较，小于为真
