#import <Foundation/Foundation.h>@class Dog;@interface Person : NSObject/** 姓名*/
@property (nonatomic, copy)NSString *name;/** 钱*/
@property (nonatomic, assign)double money;/** 宠物*/
@property (nonatomic, strong)Dog *dog;

@end

#import "Person.h"@implementation Person
{@privateint _age;
}- (void)say
{NSLog(@"age = %i", _age);
}@end

#import <Foundation/Foundation.h>@interface Dog : NSObject/** 狗的外号*/
@property (nonatomic, copy)NSString *name;/** 狗的价格*/
@property (nonatomic, assign)double price;
@end

#import "Dog.h"@implementation Dog@end

    Person *p = [[Person alloc] init];

p.name = @"chg"; // setter

p.money = 998.0;

#pragma mark 单个值//      KVC == KEY VALUE CODING// Value : 值, 只能传对象// forKey: 需要给谁(哪个属性)赋值// setValue:forKey:方法, 只能给对象的直接属性赋值[p setValue:@"lmj" forKey:@"name"];// @(998.0) == [NSNumber numberWithDouble:(double)][p setValue:@(668.0) forKey:@"money"];

#pragma mark 多层赋值p.dog = [Dog new];p.dog.name == [[p dog] setName:]p.dog.name = @"wangwang";p.dog.price = 110.0;// setValue:forKeyPath: 可以给对象的间接属性赋值. 多层赋值// 建议: 以后在开发中都使用setValue:forKeyPath:[p setValue:@"xiaoqiang" forKeyPath:@"dog.name"];[p setValue:@(110) forKeyPath:@"dog.price"];

#pragma mark 给私有成员变量赋值[p setValue:@"lnj" forKey:@"_name"];[p setValue:@(30) forKey:@"_age"];SEL sel = @selector(say);[p performSelector:sel];[p say];

#pragma mark 字典转模型NSDictionary *dict = @{@"name":@"xxx",@"money": @(998.1),//                           @"score":@(100)@"dog":@{@"name":@"wangcai",@"price":@(110)}};// 注意点:// 1.如果想使用KVC进行字典转模型, 那么字典中的key必须和模型中的属性一模一样(个数 + 名称)//  this class is not key value coding-compliant for the key score.'// 2.如果使用KVC进行字典转模型, 只能对当前调用KVC方法的对象进行转换, 不能对它的属性的对象进行转换// setValuesForKeysWithDictionary:方法内部的实现原理// 1.会拿到字典中的key, 然后根据这个key取出字典中的值, 然后再根据这个key赋值给对象//   [p setValue:@"xxx" forKey:@"name"];
    [p setValuesForKeysWithDictionary:dict];NSLog(@"p.dog = %@", p.dog);NSLog(@"name = %@, money = %f", p.name, p.money); // getter

    Person *p = [Person new];p.name = @"chg";p.money = 998;p.dog = [Dog new];p.dog.name = @"wangcai";p.dog.price = 110;

#pragma mark 获取单个值NSString *name =  [p valueForKey:@"name"];NSLog(@"name = %@", name);double money = [[p valueForKey:@"money"] doubleValue];NSLog(@"money = %f", money);

#pragma mark 获取多层值NSString *dogName = [p valueForKey:@"dog.name"];NSString *dogName = [p valueForKeyPath:@"dog.name"];NSLog(@"dogName = %@", dogName);

#pragma mark 模型转字典NSDictionary *dict = [p dictionaryWithValuesForKeys:@[@"name", @"money"]];

#pragma mark 获取数组中对象的值Person *p1 = [Person new];p1.name = @"zs";p1.money = 111;Person *p2 = [Person new];p2.name = @"ls";p2.money = 222;Person *p3 = [Person new];p3.name = @"ww";p3.money = 666;NSArray *arr = @[p1, p2, p3];// 如果数组中的元素都是同一种类型的数据, 可以使用KVC获取数组中所有对象的某个属性的值NSArray *res = [arr valueForKeyPath:@"name"];NSLog(@"res = %@", res);

#pragma mark 运算符// 获取arr数组中money的平均值id res1 = [arr valueForKeyPath:@"@avg.money"];// 获取arr数组中money的最大值id res2 = [arr valueForKeyPath:@"@max.money"];// 获取arr数组中money的最小值id res3 = [arr valueForKeyPath:@"@max.money"];NSLog(@"res1 = %@，res2 = %@，res3 = %@", res1,res2，res3);