【转】NSArray排序方法

原文网址：http://www.cnblogs.com/xiaobaizhu/archive/2013/06/05/3119983.html

从网上查的，非常方便的排序api，功能也很强大

1.sortedArrayUsingSelector

（按Key值大小对NSDictionary排序）

NSMutableArray *array = [NSMutableArray arrayWithObjects:
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj0", [NSNumber numberWithInt:0], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj5", [NSNumber numberWithInt:5], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj2", [NSNumber numberWithInt:2], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj3", [NSNumber numberWithInt:3], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj1", [NSNumber numberWithInt:1], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj4", [NSNumber numberWithInt:4], nil], nil];
    
NSArray *resultArray = [array sortedArrayUsingSelector:@selector(compare:)];

因为NSDictionary没有compare的排序比较方法，所以需要我们自己写一个

- (NSComparisonResult)compare: (NSDictionary *)otherDictionary
{
    NSDictionary *tempDictionary = (NSDictionary *)self;
    
    NSNumber *number1 = [[tempDictionary allKeys] objectAtIndex:0];
    NSNumber *number2 = [[otherDictionary allKeys] objectAtIndex:0];
    
    NSComparisonResult result = [number1 compare:number2];
    
    return result == NSOrderedDescending; // 升序
//    return result == NSOrderedAscending;  // 降序
}

2.sortedArrayUsingComparator

    NSMutableArray *array = [NSMutableArray arrayWithObjects:
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj0", [NSNumber numberWithInt:0], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj5", [NSNumber numberWithInt:5], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj2", [NSNumber numberWithInt:2], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj3", [NSNumber numberWithInt:3], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj1", [NSNumber numberWithInt:1], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj4", [NSNumber numberWithInt:4], nil], nil];
    
//    NSArray *resultArray = [array sortedArrayUsingSelector:@selector(compare:)];
    
    NSArray *resultArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        
        NSNumber *number1 = [[obj1 allKeys] objectAtIndex:0];
        NSNumber *number2 = [[obj2 allKeys] objectAtIndex:0];
        
        NSComparisonResult result = [number1 compare:number2];
        
        return result == NSOrderedDescending; // 升序
//        return result == NSOrderedAscending;  // 降序
    }];

3.sortedArrayUsingDescriptors & sortUsingDescriptors

前者带返回值，是NSArray的方法，排好序的数组是返回值中的数组；

后者不带返回值，是NSMutableArray的方法，是对当前数组自己排序

接下来根据一个对象的属性，排列这个对象

.h
@interface Person : NSObject
{
    NSString  *_name;
    
    NSInteger  _age;
}
@property (nonatomic, retain) NSString  *name;
@property (nonatomic, assign) NSInteger  age;
@end

.m
@implementation Person
@synthesize name = _name;
@synthesize age  = _age;


- (void)dealloc
{
    [_name release];
    
    [super dealloc];
}

@end

排序方法的实现

    Person *person1 = [[Person alloc] init];
    [person1 setName:@"ABC"];
    [person1 setAge:24];
    
    Person *person2 = [[Person alloc] init];
    [person2 setName:@"ACB"];
    [person2 setAge:22];
    
    Person *person3 = [[Person alloc] init];
    [person3 setName:@"ABD"];
    [person3 setAge:33];
    
    NSMutableArray *array = [NSMutableArray arrayWithObjects:person1, person2, person3, nil];
    [person1 release];
    [person2 release];
    [person3 release];
    //这里类似KVO的读取属性的方法，直接从字符串读取对象属性，注意不要写错
    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"_age" ascending:YES];
    //这个数组保存的是排序好的对象
    NSArray *tempArray = [array sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
    
    for(NSInteger i = 0; i < [tempArray count]; i++)
    {
        NSLog(@"%@--------%d
", [[tempArray objectAtIndex:i] name], [[tempArray objectAtIndex:i] age]);
    }
//下面是可变数组的方法   
//    [array sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
//    
//    for(NSInteger i = 0; i < [array count]; i++)
//    {
//        NSLog(@"%@--------%d
", [[array objectAtIndex:i] name], [[array objectAtIndex:i] age]);
//    }

   NSSortDescriptor *sortDescriptor1 = [NSSortDescriptorsortDescriptorWithKey:@"_age"ascending:YES];

   NSSortDescriptor *sortDescriptor2 = [NSSortDescriptorsortDescriptorWithKey:@"_name"ascending:YES];

   NSArray *tempArray = [array sortedArrayUsingDescriptors:[NSArrayarrayWithObjects:sortDescriptor1, sortDescriptor2, nil]];

   这里的NSArray中的第一元素表示首先按照这个元素的升序或者降序进行排序,对于有重复项的，再按照第二元素进行排序，依次进行类推

 

ios 开发 NSArray 排序

原文网址：http://blog.csdn.net/wenluma/article/details/8705272

NSMutableArray *array =  [[NSMutableArray alloc] initWithObjects:@"1",@"3",@"5",@"40" nil];</span></p>NSArray *sorteArray = [array sortedArrayUsingComparator:^(id obj1, id obj2){
    if ([obj1 integerValue] > [obj2 integerValue]) {
        return (NSComparisonResult)NSOrderedDescending;
    }

    if ([obj1 integerValue] < [obj2 integerValue]) {
        return (NSComparisonResult)NSOrderedAscending;
    }

    return (NSComparisonResult)NSOrderedSame;
}];

NSLog(@"%@",sorteArray);            //从小到大


NSArray *array2 = [array sortedArrayUsingComparator:^(id obj1, id obj2){
    if ([obj1 integerValue] > [obj2 integerValue]) {
        return (NSComparisonResult)NSOrderedAscending;
    }

    if ([obj1 integerValue] < [obj2 integerValue]) {
        return (NSComparisonResult)NSOrderedDescending;
    }

    return (NSComparisonResult)NSOrderedSame;
}];

NSLog(@"%@",array2);

以上包含了有从小到大的排序，也包含有大到小的排序

如果是针对字符串的排序，有更好的方法，

NSArray *ary = @[@"a3",@"a1",@"a2",@"a10",@"a24"];
NSLog(@"%@",ary);
NSArray *myary = [ary sortedArrayUsingComparator:^(NSString * obj1, NSString * obj2){
    return (NSComparisonResult)[obj1 compare:obj2 options:NSNumericSearch];
}];
NSLog(@"%@",myary);
结果
 ( a3,a1, a2, a10, a24 )
 ( a1, a2,a3, a10, a24 )

NSArray *ary = @[@"a3",@"a1",@"a2",@"a24",@"a14"];
NSLog(@"%@",ary);
NSSortDescriptor *sd1 = [NSSortDescriptor sortDescriptorWithKey:nil ascending:NO];//yes升序排列，no,降序排列
NSArray *myary = [ary sortedArrayUsingDescriptors:[NSArray arrayWithObjects:sd1, nil]];//注意这里的ary进行排序后会生产一个新的数组指针，myary，不能在用ary,ary还是保持不变的。
NSLog(@"%@",myary);
//    (a3, a1, a2,a24,a14)
//    (a3, a24, a2, a14, a1)

[ary sortedArrayUsingSelector:@selector(compare:)];//这个是一直默认升序