[oc学习笔记]数组的遍历和排序

 1         //数组的遍历(可变数组举例) 2         //for遍历 3         NSMutableArray *aa = [NSMutableArray array]; 4         [aa addObjectsFromArray:@[@"ss",@"ddd",@"sad"]]; 5         for (int i = 0;  i < aa.count; i++) { 6             NSLog(@"%@",[aa objectAtIndex:i]); 7         } 8         //快速遍历 9         for (id obj in aa) {10             NSLog(@"%@",obj);11         }12         //代码块遍历13         // obj是对象 idx是下标 stop是停止标志14         [aa enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {15             NSLog(@"%@",obj);16             NSLog(@"%@",[aa objectAtIndex:idx]);17         }];18         //迭代器遍历19         //将数组元素存放进迭代器20         NSEnumerator *en = [aa objectEnumerator];21         id obj = nil;//创建一个对象接受返回对象22         while (obj = [en nextObject]) {23             NSLog(@"%@",obj);24         }25         //反向迭代器遍历26         NSEnumerator *en1 = [aa reverSEObjectEnumerator];27         id obj1 = nil;28         while (obj1 = [en1 nextObject]) {29             NSLog(@"%@",obj1);30         }31         32         33         //排序(可变数组举例)34         //可变数组排序的方法无返回值 不可变数组的排序有返回值35         //选择器排序36         //compare方法尽限于比较元素是字符时 ，如有另外的比较 请另写比较方法 返回值（NSComparisonResult）37         [aa sortUsingSelector:@selector(compare:)];38         //代码块排序39         //根据实际情况写判断方法40         [aa sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {41             return [obj1 compare:obj2];42         }];43         //比较描述器排序44         //对多个条件进行排序比较便利45         Person *p1 = [[Person alloc]init];46         p1.name = @"ss";47         p1.age = @"16";48         49         Person *p2 = [[Person alloc]init];50         p2.name = @"dd";51         p2.age = @"14";52         53         Person *p3 = [[Person alloc]init];54         p3.name = @"hh";55         p3.age = @"22";56         57         Person *p4 = [[Person alloc]init];58         p4.name = @"hh";59         p4.age = @"19";60         NSMutableArray *sss = [NSMutableArray arrayWithObjects:p1,p2,p3,p4,nil];61         NSSortDescriptor *sort1 = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];62         NSSortDescriptor *sort2 = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES];63         NSArray *s = @[sort1,sort2];64         [sss sortUsingDescriptors:s];65         NSLog(@"%@",sss);

1 #import <Foundation/Foundation.h>2 3 @interface Person : NSObject4 @PRoperty (nonatomic,strong)NSString *name;5 @property (nonatomic,strong)NSString *age;6 @end

1 #import "Person.h"2 3 @implementation Person4 - (NSString *)description5 {6     return [NSString stringWithFormat:@"%@ %@", _name,_age];7 }8 @end

2015-06-01 17:37:55.984 Array[2030:140148] ss2015-06-01 17:37:55.985 Array[2030:140148] ddd2015-06-01 17:37:55.985 Array[2030:140148] sad2015-06-01 17:37:55.986 Array[2030:140148] ss2015-06-01 17:37:55.986 Array[2030:140148] ddd2015-06-01 17:37:55.986 Array[2030:140148] sad2015-06-01 17:37:55.986 Array[2030:140148] ss2015-06-01 17:37:55.986 Array[2030:140148] ss2015-06-01 17:37:55.986 Array[2030:140148] ddd2015-06-01 17:37:55.987 Array[2030:140148] ddd2015-06-01 17:37:55.987 Array[2030:140148] sad2015-06-01 17:37:55.987 Array[2030:140148] sad2015-06-01 17:37:55.992 Array[2030:140148] ss2015-06-01 17:37:55.992 Array[2030:140148] ddd2015-06-01 17:37:55.992 Array[2030:140148] sad2015-06-01 17:37:55.992 Array[2030:140148] sad2015-06-01 17:37:55.992 Array[2030:140148] ddd2015-06-01 17:37:55.993 Array[2030:140148] ss2015-06-01 17:37:55.993 Array[2030:140148] (    "dd 14",    "hh 19",    "hh 22",    "ss 16")