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:@"113" forKey:@"name"];
    NSLog(@"%@",[dict2 objectForKey:@"name"]);