Objective-C 字典、可变字典

字典相当于c++ stl中的map

字典NSDictionary

 #import <UIKit/UIKit.h>
 #import "AppDelegate.h"

 int main(int argc, char * argv[]) {
     // 从@符号创建字典  实际上就是键值对容器
     NSDictionary *dict = @{@"name":@"zhangsan",@"sex":@"male"};
     NSLog(@"%@",dict);

     // 根据键获取值
     NSLog(@"%@",[dict objectForKey:@"name"]);

     // 从配置文件中读取
     NSDictionary *dict1 = [NSDictionary dictionaryWithContentsOfFile:
         [[NSBundle mainBundle] pathForResource:@"data" ofType:@"plist" ]];
     NSLog(@"%@",[dict1 objectForKey:@"name"]);
     NSLog(@"%@",[dict1 objectForKey:@"age"]);

         @autoreleasepool {
         return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
     }
 }

可变字典 NSMutableDictionary

     NSMutableDictionary *dict2 = [[NSMutableDictionary alloc]init];
     // setObject 可以新增key 也可以修改已有key的值
     [dict2 setObject:@"jinpangpang" forKey:@"name"];
     [dict2 setObject:@"" forKey:@"name"];
     NSLog(@"%@",[dict2 objectForKey:@"name"]);