OC中的字典

/******* NS Dictionary ********

//创建字典的方式：

// NSDictionary *dic1=[[NSDictionary alloc]init];

// NSDictionary *dic2=[NSDictionary dictionary];//创建可变空字典；

NSDictionary *dictionary1=[NSDictionary dictionaryWithObject:@"Value" forKey:@"key"];

NSLog(@"dictionary1:%@",dictionary1);

NSDictionary *dictionary2=[[NSDictionary alloc]initWithObjects:@[@"V1",@"V2",@"V3"] forKeys:@[@"k1",@"k2",@"k3"]];

NSLog(@"dictionary2:%@",dictionary2);

NSDictionary *dictionary3=[NSDictionary dictionaryWithObjectsAndKeys:@"V1",@"k1",@"V2",@"k2", nil];

NSLog(@"dictionary3%@",dictionary3); //必须是一一对应

//自己封装一个包涵从学生信息的字典

NSString *stu_name=@"Tom";

NSArray *stu_score=@[@90,@100,@80];

NSArray *valueArray=@[@20,stu_name,stu_score];

NSDictionary *stuDic=[NSDictionary dictionaryWithObjects:valueArray forKeys:@[@"age",@"name",@"score",]];

NSLog(@"%@",stuDic);

//根据已有字典创建新的字典

NSDictionary *dictionary4=[NSDictionary dictionaryWithDictionary:dictionary3];

NSLog(@"dictionary4%@",dictionary4);

//获取字典中所有元素（键值对）的个数

NSLog(@"dictionary4.count=%ld",dictionary4.count);

// 根据key值去获取value值

NSString *value1=[dictionary4 valueForKey:@"k1"];

NSLog(@"%@",value1);

NSArray *value_array=[stuDic valueForKey:@"score"];

NSLog(@"%@",value_array);

//获取字典中所有的key

NSArray *keyArray=[dictionary4 allKeys];

NSArray *value_Array=[stuDic allValues];

NSLog(@"%@%@",keyArray,value_Array);

/********** NSMutableDictionary **********

NSMutableDictionary *mutableDic1=[NSMutableDictionary dictionaryWithObjects:@[@"V1",@"V2",@"V3"] forKeys:@[@"k1",@"k2",@"k3"]];

//添加

[mutableDic1 setObject:@"V4" forKey:@"k3"];//替换原来的值

NSLog(@"%@",mutableDic1);

//根据已经存在的字典添加

[mutableDic1 addEntriesFromDictionary:dictionary4];

NSLog(@"%@",mutableDic1);

//修改

//将当前字典所有元素替换成新的字典中的元素

NSDictionary *dictionary=[NSDictionary dictionaryWithObjects:@[@"A",@"B"] forKeys:@[@"A1",@"B1"]];

[mutableDic1 setDictionary:dictionary];

NSLog(@"%@",mutableDic1);

//指定key值修改

[mutableDic1 setObject:@"newA" forKey:@"A1"];

NSLog(@"%@",mutableDic1);

// 删除

[mutableDic1 removeObjectForKey:@"B1"];//指定key值删除

[mutableDic1 removeObjectsForKeys:@[@"A1",@"B1"]];//指定多个key删除

[mutableDic1 removeAllObjects];//删除所有