NSMutableDictionary的基本使用 - OC

可变字典的创建
//1)可变字典的创建
NSMutableDictionary *dict1 = [NSMutableDictionary dictionary]; //创建空字典
NSMutableDictionary *dict2 = [NSMutableDictionary dictionaryWithCapacity:3];

增
[dict1 setValue:@"zhaosi" forKey:@"ls"];//因为key值重复了,所以添加不上
[dict1 setValue:@"lisi" forKey:@"ls"]; // ls

  [dict1 setValue:@"liuneng" forKey:@"ln"];
  NSLog(@"%@",dict1);

删
[dict1 removeObjectForKey:@"ls"];
//全部删除
// [dict1 removeAllObjects];

改
[dict1 setObject:@"zhaosi" forKey:@"ls"];
//简写形式
dict1[@"ls"] = @"xxxxx";
NSLog(@"%@",dict1);

查
//获取所有的key值
NSArray *arr = [dict1 allKeys];
if([arr containsObject:@"ls"]){

      NSLog(@"存在ls的key");
  }