OC学习总结3

NSSet *set=[[NSSet alloc] initWithObjects:@"one",@"two",@"three",@"four",nil];
NSLog(@"%@",set); 输出结果无序
NSSet *set2=[[NSSet alloc] initWithObjects:@"one",@"three",@"two",@"four",nil];
BOOL ret =[set isEqualToSet:set2];
NSLog(@"%d",ret);返回值YES 1
BOOL ret =[set isSubsetOfSet:set2];判断第一个集合是否是第二个集合的子集合 返回值YES 1

1 创建可变集合
NSMutableSet *set=[NSMutableSet set];
[set addObject:@"One"];
[set addObject:@"two"];
[set addObject:@"three"];
[set addObject:@"Two"];
NSLog(%"%@",set);输出One two three，两个two只保留一个
2 删除集合中的元素
[set removeObject:@"three"];还剩 One two
3 添加
NSSet *set2=[NSSet setWithObject:@"five",@"six",@"one",nil];
[set unionSet:set2];把set2中的内容合并到set中
[set minusSet:set2];把set2中的内容从set1中删除，只剩two了
##NSIndexSet 
指数集合 索引集合 是一个变种，和NSSet没有继承关系

1 创建
NSDate *now =[NSDate date];
NSLog(@"now>>>>%@",now);
输出 2015-07-20 6：44：20 +0000 比现在慢8小时，北京东8区，时区

2 通过时间差获取另外一个时间
NSTimeInterval interval=60*60*24;
NSDate *yesterday=[now dateByAddingTimeInterval:-interval];
%@ yesterday 输出昨天的时间
NSDate *tomorrow=[now dateByAddingTimeInterval:interval];
%@ tomorrow 输出明天的时间
NSDate *someDate = [NSDate dateWithTimeInterval:-60*60*24*7 sinceDate:tomorrow];
NSLog(@"someDate >>>> %@", someDate);
NSDate *date1 = [NSDate dateWithTimeIntervalSinceReferenceDate:60*60*24*365*15];
NSLog(@"date1 >>>> %@", date1);    
3 判断 比较日期
now isEqualToDate:tomorrow
NSDate *earlierDate = [tomorrow earlierDate:now]; // 早一点的日期
NSDate *laterDate = [tomorrow laterDate:now]; // 晚一点的日期
NSLog(@"earlierDate >>>> %@", earlierDate);
NSLog(@"laterDate >>>> %@", laterDate);

// 求时间差
NSTimeInterval interval1 = [now timeIntervalSinceDate:tomorrow];
NSLog(@"interval1 >>>>> %lf", interval1);

/************* NSTimeZone *************/


NSTimeZone *localZone = [NSTimeZone defaultTimeZone];
NSLog(@"localZone >>>>> %@", localZone);

NSTimeZone *Taipei = [[NSTimeZone alloc] initWithName:@"Asia/Taipei"];
NSLog(@"Taipei >>> %@", Taipei);


##NSTimeZone
1 时区
NSArray *allZone=[NSTimeZone knownTimeZoneNames];
for(NSTimeZone *zone in allZone){
NSLog(@"zone>>%@",zone);
}
2 本地默认时区
NSTimeZone *localZone=[NSTimeZone defaultTimeZone];
NSLog(@"local>>>%@",localZone); 输出Asia shanghai 亚洲上海
3 /************* NSDateFormatter *************/
// 通过对 NSDateFormatter的设置来输出任意格式的时间文本
NSDateFormatter *dateFromatter = [NSDateFormatter new];

[dateFromatter setDateStyle:NSDateFormatterShortStyle];
[dateFromatter setTimeStyle:NSDateFormatterShortStyle];

[dateFromatter setTimeZone:localZone];
NSLog(@"now >>>>>> %@", [dateFromatter stringFromDate:[NSDate date]]);

[dateFromatter setDateFormat:@"yy-M-dd HH:mm:ss 今天是第w 周 上午/下午:a "];
NSLog(@"now >>>>>> %@", [dateFromatter stringFromDate:[NSDate date]]);

// 把时间格式的字符串变成时间对象
NSString *timeStr = @"85------10/28 17:15:00";
[dateFromatter setDateFormat:@"yy------MM/dd HH:mm:ss"];
NSDate *birth = [dateFromatter dateFromString:timeStr];
NSLog(@"birth >>>> %@", birth);