//创建一个数组

    NSArray *array = @[@"one", @"two", @"three", @"four", @"six"];

    //创建一个排序条件，也就是一个NSSortDescriptor对象

    //其中第一个参数为数组中对象要按照什么属性来排序(比如自身、姓名，年龄等)

    //第二个参数为指定排序方式是升序还是降序

    //ascending  排序的意思，默认为YES 升序

    NSSortDescriptor *des = [[NSSortDescriptor alloc] initWithKey:@"self" ascending:YES];

    NSArray *newArray = [array sortedArrayUsingDescriptors:@[des]];

    NSLog(@"%@",newArray);

//创建一个Person类

    Person *p1 = [[Person alloc] initWithName:@"zhonger" age:@""];

    Person *p2 = [[Person alloc] initWithName:@"zhubada" age:@""];

    Person *p3 = [[Person alloc] initWithName:@"zhubada" age:@""];

    Person *p4 = [[Person alloc] initWithName:@"zhubada" age:@""];

    Person *p5 = [[Person alloc] initWithName:@"hehehe" age:@""];

    NSArray *person = @[p1, p2, p3, p4, p5];

    NSSortDescriptor *des1 = [[NSSortDescriptor alloc]initWithKey:@"name" ascending:YES];

    NSSortDescriptor *des2 = [[NSSortDescriptor alloc] initWithKey:@"age" ascending:NO];

    NSArray *newArray1 = [person sortedArrayUsingDescriptors:@[des1,des2]];

    NSLog(@"%@",newArray1);

NSArray *strArray = @[@"zhonger", @"zhubada", @"qiuxiang", @"tangbohu", @"honghuang"];

    NSArray *nesStr = [strArray sortedArrayUsingSelector:@selector(compare:)]; //SEL  只能用@selector（方法名）给定，并且，如果数组使用这个数组进行排序，此方法必须是返回值为NSComparisionResult

    NSLog(@"newStr is %@",nesStr);

    NSArray *personNewArray = [person sortedArrayUsingSelector:@selector(compareByName:)];

    NSLog(@"--%@",personNewArray);