摘要：
键与值一一对应，键不能重复；该值可以重复；1.创建NSDictionary：（字典的内容是无序的，无法排序）NSDictionary*dic=[NSDictionarydictionary]//创建一个空字典NSDictiontionary*dic1=[NSDDictionaryDictionary WithObject:@“object”forKey:@“key”]//NSLog，一个只有一对键的字典(
键与值一一对应，键不能重复；
值可以重复；
1.NSDictionary的创建：(字典的内容是无序的，不能进行排序)
NSDictionary *dic = [NSDictionary dictionary];//创建一个空字典
NSDictionary *dic1 = [NSDictionary dictionaryWithObject:@"object" forKey:@"key"];//只有一对键值的字典
NSLog(@"%@",dic1);
NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:@"value1",@"key1" ,@"value2",@"key2",nil];//字典的存放是无序的（没有下标的概念）（键值，键）
NSLog(@"%@",dic2);
NSDictionary *dic3 = @{
@"key1":@"123",
NSDictionary *dic1 = [NSDictionary dictionaryWithObject:@"object" forKey:@"key"];//只有一对键值的字典
NSLog(@"%@",dic1);
NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:@"value1",@"key1" ,@"value2",@"key2",nil];//字典的存放是无序的（没有下标的概念）（键值，键）
NSLog(@"%@",dic2);
NSDictionary *dic3 = @{
@"key1":@"123",
@"key2":@"456",
@"key3":@"466"
};//快速创建( @“键”：@“键值” )要用大括号！
NSLog(@"%@",dic3);
dic3 = @{@"1":@"hguf",
@"2":@"dfgdsf",
@"3":@"vbrthf"
dic3 = @{@"1":@"hguf",
@"2":@"dfgdsf",
@"3":@"vbrthf"
};//对dic3重新初始化，并没有改变内容；
1.NSDictionary的使用：
long int count = dic3.count;//字典的长度，键值对个数：
NSLog(@"%zi",count);
NSString *s = [dic3 objectForKey:@"2"];//获取某key对应的值；
NSLog(@"%@",s);
NSString *s1 = dic3[@"3"];//获取某key对应的值；
NSLog(@"%@",s1);
//遍历：
//获取key；
NSArray *keyarr = [dic3 allKeys];
for(NSString *key in keyarr)
NSString *s = [dic3 objectForKey:@"2"];//获取某key对应的值；
NSLog(@"%@",s);
NSString *s1 = dic3[@"3"];//获取某key对应的值；
NSLog(@"%@",s1);
//遍历：
//获取key；
NSArray *keyarr = [dic3 allKeys];
for(NSString *key in keyarr)
NSLog(@"%@=%@",key,dic3[key]);
1=hguf
2=dfgdsf
2=dfgdsf
3=vbrthf
//获取值
NSArray *valuearr = [dic3 allValues];
for(NSString *value in valuearr)
NSLog(@"%@",value);
NSArray *valuearr = [dic3 allValues];
for(NSString *value in valuearr)
NSLog(@"%@",value);
hguf
dfgdsf
vbrthf
NSEnumerator *e = [dic3 keyEnumerator];//先获取字典中key的枚举器，然后遍历该枚举器，获取key对应的值
id k;
while(k=[e nextObject])
id k;
while(k=[e nextObject])
NSLog(@"%@ = %@",k,dic3[k]);
1 = hguf
2 = dfgdsf
2 = dfgdsf
3 = vbrthf
NSEnumerator *e1 = [dic3 objectEnumerator];//获取字典中值的枚举器
id value;
while(value=[e1 nextObject])
id value;
while(value=[e1 nextObject])
结果： NSLog(@"%@",value);
hguf
dfgdsf
vbrthf
[dic3 enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) { NSLog(@"key=%@,value=%@",key,obj);
}];//stop代表遍历停止
运行结果：
key=1,value=hguf
key=2,value=dfgdsf
key=3,value=vbrthf