数据排序（规则 如果有相同的姓，就比较名字）

https://blog.csdn.net/daiyelang/article/details/18726947

#pragma mark 数组排序1

voidarraySort1() {

NSArray*array = [NSArrayarrayWithObjects:@"2",@"3",@"1",@"4",nil];

// 返回一个排好序的数组，原来数组的元素顺序不会改变

// 指定元素的比较方法：compare:

NSArray*array2 = [array sortedArrayUsingSelector:@selector(compare:)];

NSLog(@"array2:%@", array2);

}

#pragma mark 数组排序2

voidarraySort2() {

Student *stu1 = [Student studentWithFirstname:@"MingJie"lastname:@"Li"];

Student *stu2 = [Student studentWithFirstname:@"LongHu"lastname:@"Huang"];

Student *stu3 = [Student studentWithFirstname:@"LianJie"lastname:@"Li"];

Student *stu4 = [Student studentWithFirstname:@"Jian"lastname:@"Xiao"];

NSArray*array = [NSArrayarrayWithObjects:stu1,stu2,stu3, stu4,nil];

// 指定排序的比较方法

NSArray*array2 = [array sortedArrayUsingSelector:@selector(compareStudent:)];

NSLog(@"array2:%@", array2);

}

- (NSComparisonResult)compareStudent:(Student *)stu {

// 先按照姓排序

NSComparisonResultresult = [self.lastname compare:stu.lastname];

// 如果有相同的姓，就比较名字

if(result ==NSOrderedSame) {

result = [self.firstname compare:stu.firstname];

    }

returnresult;

}

#pragma mark 数组排序3

voidarraySort3() {

Student *stu1 = [Student studentWithFirstname:@"MingJie"lastname:@"Li"];

Student *stu2 = [Student studentWithFirstname:@"LongHu"lastname:@"Huang"];

Student *stu3 = [Student studentWithFirstname:@"LianJie"lastname:@"Li"];

Student *stu4 = [Student studentWithFirstname:@"Jian"lastname:@"Xiao"];

NSArray*array = [NSArrayarrayWithObjects:stu1,stu2,stu3, stu4,nil];

// 利用block进行排序

NSArray*array2 = [array sortedArrayUsingComparator:

^NSComparisonResult(Student *obj1, Student *obj2) {

// 先按照姓排序

NSComparisonResultresult = [obj1.lastname compare:obj2.lastname];

// 如果有相同的姓，就比较名字

if(result ==NSOrderedSame) {

            result = [obj1.firstname compare:obj2.firstname];

        }

returnresult;

    }];

NSLog(@"array2:%@", array2);

}

#pragma mark 数组排序4-高级排序

voidarraySort4() {

Student *stu1 = [Student studentWithFirstname:@"MingJie"lastname:@"Li"bookName:@"book1"];

Student *stu2 = [Student studentWithFirstname:@"LongHu"lastname:@"Huang"bookName:@"book2"];

Student *stu3 = [Student studentWithFirstname:@"LianJie"lastname:@"Li"bookName:@"book2"];

Student *stu4 = [Student studentWithFirstname:@"Jian"lastname:@"Xiao"bookName:@"book1"];

NSArray*array = [NSArrayarrayWithObjects:stu1,stu2,stu3, stu4,nil];

// 1.先按照书名进行排序

// 这里的key写的是@property的名称

NSSortDescriptor*bookNameDesc = [NSSortDescriptorsortDescriptorWithKey:@"book.name"ascending:YES];

// 2.再按照姓进行排序

NSSortDescriptor*lastnameDesc = [NSSortDescriptorsortDescriptorWithKey:@"lastname"ascending:YES];

// 3.再按照名进行排序

NSSortDescriptor*firstnameDesc = [NSSortDescriptorsortDescriptorWithKey:@"firstname"ascending:YES];

// 按顺序添加排序描述器

NSArray*descs = [NSArrayarrayWithObjects:bookNameDesc, lastnameDesc, firstnameDesc,nil];

NSArray*array2 = [array sortedArrayUsingDescriptors:descs];

NSLog(@"array2:%@", array2);

}