数组排序：对象数组中根据对象的某个字段排序

1. 开发中，经常碰到数组的排序问题，当然原始的冒泡、选择排序，还是比较好用的。
2. 我们常常需要后台排好序再返回，当然也有需要前端排序的。我觉得数组的排序，根据对象数组的某个字段排序，是非常常见的。现在来说说：

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• sortedArrayUsingSelector

 - (void)sortArray1{    NSArray *tempArray = [NSArray arrayWithObjects:@"abc",@"123",@"bac",@"345",@"Abc", nil];    //compare:使用的是字符串自带的方法    NSArray *sortArray = [tempArray sortedArrayUsingSelector:@selector(compare:)];    NSLog(@"%@",sortArray);}

这种是最简单的排序。直接对数组进行排序。
- 我们看自定义compare的

//Car类 .h文件@interface Car : NSObject@property(nonatomic,copy)NSString *carId;@property(nonatomic,assign)int carBuyTime;+ (instancetype)CarWithCarId:(NSString *)carId andCarBuyTime:(int)carBuyTime;- (NSComparisonResult)compareCar:(Car *)car;@end//.m 文件#import "Car.h"@implementation Car+ (instancetype)CarWithCarId:(NSString *)carId andCarBuyTime:(int)carBuyTime{    Car *car = [[Car alloc]init];    car.carId = carId;    car.carBuyTime = carBuyTime;    return car;}- (NSComparisonResult)compareCar:(Car *)car{    //先按照购买时间排序   NSComparisonResult result = [[NSNumber numberWithInt:car.carBuyTime]compare:[NSNumber numberWithInt:self.carBuyTime]];    if (result == NSOrderedSame) {      result =   [car.carId compare:car.carId];    }    return  result;}@end

控制器调用：

- (void)sortArray2{    Car *car2 = [Car CarWithCarId:@"87323" andCarBuyTime:1988];    Car *car3 = [Car CarWithCarId:@"87323" andCarBuyTime:1962];    Car *car4 = [Car CarWithCarId:@"66666" andCarBuyTime:1970];    Car *car1 = [Car CarWithCarId:@"32311" andCarBuyTime:1970];    NSArray *array = [NSArray arrayWithObjects:car1,car2,car3,car4, nil];   NSArray *sortedArray =  [array sortedArrayUsingSelector:@selector(compareCar:)];    NSLog(@"%@",sortedArray);}

输出：

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• sortedArrayUsingComparator

- (void)sortArray3{    Car *car2 = [Car CarWithCarId:@"87323" andCarBuyTime:1988];    Car *car3 = [Car CarWithCarId:@"87323" andCarBuyTime:1962];    Car *car4 = [Car CarWithCarId:@"66666" andCarBuyTime:1970];    Car *car1 = [Car CarWithCarId:@"32311" andCarBuyTime:1970];    NSArray *array = [NSArray arrayWithObjects:car1,car2,car3,car4, nil];  array =   [array sortedArrayUsingComparator:^NSComparisonResult(Car * obj1, Car * obj2) {      NSComparisonResult result = [[NSNumber numberWithInt:obj1.carBuyTime]compare:[NSNumber numberWithInt:obj2.carBuyTime]];      if (result == NSOrderedSame) {          result =   [obj1.carId compare:obj2.carId];      }      return  result;    }];}