OC关于NSDictionary和NSMutableDictionary方法的使用

//1.通过 值数组和键数组作为参数定义字典

NSDictionary *dict=[[NSDictionary alloc] initWithObjects:@[@"0ne",@"two"] forKeys:@[@"1",@"2"]];

NSDictionary *dicT=[NSDictionary dictionaryWithObjects:@[@"0ne",@"two"] forKeys:@[@"1",@"2"]];

//2.直接通过赋 值和键 来定义

NSDictionary *dict3=

[[NSDictionary alloc]initWithObjectsAndKeys:@"guangzhou",@"1",@"champions",@"2",@"2013",@"3",nil];

//3.前面是键，后面是值

NSDictionary *dict5=@{@"1":@"guoan",@"2":@"no.1",@"3":@"forever"};

NSLog(@"%@",dict);

NSLog(@"%@",dict3);

NSLog(@"%@",dict5);

//返回字典 值或键的个数

NSUInteger len= [dict3 count];

//通过 键找到值

NSString *str=[dict3 objectForKey:@"2"];

NSLog(@"len=%lu--%@",len,str);

//返回字典中所有的键

NSArray *arrayKey3=[dict3 allKeys];

//返回字典中所有的值

NSArray *arrayObject3=[dict3 allValues];

NSLog(@"key-%@\n object-%@",arrayKey3,arrayObject3);

//快速枚举法

for (NSString *key in [dict5 allKeys]) {

//快速枚举法只能遍历字典中的键

NSLog(@"%@",[dict5 objectForKey:key]);

//通过键再找到值

}

//可变字典

NSMutableDictionary *dictM=

[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"beijing",@"1",@"welcome",@"2",@"to",@"3",@"you",@"4", nil];

NSLog(@"dictM-%@",dictM);

//重置字典

[dictM setDictionary:dict5];

//添加键值对

[dictM setObject:@"beijing" forKey:@"qianfeng"];

NSLog(@"%@",dictM);

//删除键值对

[dictM removeObjectForKey:@"qianfeng"];

NSLog(@"%@",dictM);