objective-c 基础语法学习之--（4）NSDictionary

字典的key值不能为空

如果需要空值，可以赋值为NSNULL；

//**********************************创建*************************************************

NSDictionary dic = [NSDctionary dictionaryWithObject:@"nihao"  forKey:@"one"];

NSDictionary dic2 = [NSDictionary dictionaryWtihObjectsAndKeys:@"a",@"one",@"b",@"two",nil];

NSDictionary dic3 = [NSDictionary dictionaryWithDictionary:dic2];

*************************************获取内容*********************************************

NSLog("%@",dic3);可以直接打印

NSInteger count = [dic3 count];//

NSString str = [dic3 objectForKey:@"two"];//

NSArray *keysArr = [dic3 allKeys];//

NSArray *valuesArr = [dic3 allValues];//

//********""****************************可变字典***********************************************

NSMutableDictionary mdic

= [NSMutableDictionary dictionaryWithObjectsAndKeys:@"chinese",@"one",@"USA",@"two",nil];//

[mdic addEntriesFromDictionary:dic3];//创建

[mdic setValue:@"Japan" forKey:@"three"];//插入

[mdic removeObjectForKey:@"one"];//删除

[mdic removeObjectsForKeys:array];？？？？？

//*************************************遍历*********************************************

for(int i=0;i<[dic3 count];i++){

       id key = [dic3 objectAtIndex:i];

       id value = [dic3 objectForKey:key];

NSLog(@"%@",value);

}

//******************************************

for(id key  in dic3){

    NSString *str = [dic3  objectForKey:key];

    NSLog();

}

//******************************************

MSEnumarator  *enumarator = [dic3 keyEnumarator ]；

id key = [enumarator nextObject];

id object;

while(key)

{

      object = [dic3 objectForKey:key];

      NSLog();

      key = [enumarator nextObject];

}