OC基础 Foundation基础 NSDictionary

OC中的所有集合对象（NSArry,NSSet,NSDictionary）只能存储OC对象，不能存储基本数据类型 （char short int long float double）和结构体类型数值

main

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSDictionary* dic =[NSDictionary dictionaryWithObject:@1 forKey:@"1"];
        NSDictionary* dic2=@{@"1":@1,@"2":@2};
        NSDictionary* dic3=[NSDictionary dictionaryWithObjectsAndKeys:@1,@"1",@2,@"2", nil];
        NSArray* objs=@[@1,@2];
        NSArray* keys=@[@"1",@"2"];
        NSDictionary* dic4 =[NSDictionary dictionaryWithObject:objs forKey:keys];
        
        //字典对象的使用
        id obj =[dic2 objectForKey:@"2"];
        NSLog(@"%@",obj);
        
        for(id key in dic3)
        {
            id obj =[dic2 objectForKey:key];
            NSLog(@"%@",obj);
        }
        
        // 用法 联系人的信息
        NSDictionary* contact = @{@"name":@"Tom",@"age":@25,@"tel":@"15645530792",@"email":@"786577908@qq.com"};
        NSDictionary* contact2 = @{@"name":@"Tom2",@"age":@35,@"tel":@"156455307923",@"email":@"786577908@qq.com"};
        
        NSMutableArray* contractbook=[[NSMutableArray alloc] init];
        [contractbook addObject:contact];
        [contractbook addObject:contact2];
        // 并不是按照顺序 也是hash table
        NSLog(@"%@",contractbook);
        
        
        
        
    }
    return 0;
}

拓展

        // 在字典中 key必须是唯一的 不能重复
        NSDictionary* contact3 = @{@"name":@"Tom",@"age":@25,@"tel":@"15645530792",@"email":@"786577908@qq.com",@"name":"Smish"};

        NSLog(@"%@",contact3);
//         字典中block遍历
        [contact2 enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
            NSLog(@"%@:,%@",key,obj);
        }];

//        字典对象写到文件中
        [contact2 writeToFile:<#(nonnull NSString *)#> atomically:(BOOL)];
        
//        通过读文件创建字典对象
        NSDictionary* contract4=[NSDictionary dictionaryWithContentsOfFile:<#(nonnull NSString *)#>]
    
    // 可变的字典对象
    NSMutableDictionary* mutableDic=[[NSMutableDictionary alloc]init];
    [mutableDic setDictionary:contact];
    //移除
    [mutableDic removeObjectForKey:@"email"];
    NSLog(@"%@",mutableDic);
    //移除多个
    [mutableDic removeObjectsForKeys:@[@"age",@"tel"]];
    NSLog(@"%@",mutableDic);
    //新增一个对象
    [mutableDic setObject:@30 forKey:@"age"];
    NSLog(@"%@",mutableDic);