Objective-C----快速枚举、数组排序

直接上代码：

        /*         *  快速枚举         *         */        NSLog( @"++++++++++++++++++" ) ;        NSArray *testArray = @[@1, @2, @3, @4, @5] ;        //通过快速枚举来遍历数组元素        for (NSArray *object in testArray) {            NSLog( @"%@", object ) ;        }        //不确定类型时用 id        for ( id object in testArray ) {            NSLog( @"%@", object ) ;        }        //快速遍历集合        for ( id object in set1 ) {            NSLog( @"%@", object ) ;        }        //快速遍历字典(得到的是字典的键)        //直接遍历字典得到的是字典的每一个键，可以通过遍历得到的键去获取对应的值        for ( id object in dic1 ) {            NSLog( @"%@", object ) ;        }        //dic1[key]可得到对应value，这是一个语法糖，相当于[dic1 objectForKey:key]        for ( NSString *key in dic1) {            NSLog( @"dictionary[%@]:%@", key, dic1[key] ) ;        }        /*         *  数组排序         *         */        //注意初始化数组时，所有数组元素对象的类型相同，如下会出错：@[@1, @2, @"5", @3, @4]        NSArray *array1 = @[@1, @2, @5, @3, @4] ;        //使用数组排序方法对数组进行升序排序        NSArray *resultArray = [array1 sortedArrayUsingSelector:@selector(compare:)] ;        NSLog( @"%@", resultArray ) ;        Student *stu1 = [Student studentWithName:@"wang" score:@85] ;        Student *stu2 = [Student studentWithName:@"zhen" score:@95] ;        Student *stu3 = [Student studentWithName:@"gang" score:@65] ;        NSMutableArray *stus = [NSMutableArray array] ;        [stus addObject:stu1] ;        [stus addObject:stu2] ;        [stus addObject:stu3] ;        [stus sortedArrayUsingSelector:@selector(scoreAscending:)] ;        NSLog( @"%@", stus ) ;        [stus sortedArrayUsingSelector:@selector(scoreDescending:)] ;        NSLog( @"%@", stus ) ;        [stus sortedArrayUsingSelector:@selector(nameAscending:)] ;        NSLog( @"%@", stus ) ;        [stus sortedArrayUsingSelector:@selector(nameDescending:)] ;        NSLog( @"%@", stus ) ;