NSDictionary使用小结

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{

@autoreleasepool {

//创建字典
NSDictionary *dic1 = [NSDictionary dictionaryWithObject:@"value" forKey:@"key"];
NSLog(@"dic1 :%@", dic1);

//创建多个字典
NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:
@"value1", @"key1",
@"value2", @"key2",
@"value3", @"key3",
@"value4", @"key4",
nil];
NSLog(@"dic2 :%@", dic2);

//根据现有的字典创建字典
NSDictionary *dic3 = [NSDictionary dictionaryWithDictionary:dic2];
NSLog(@"dic3 :%@", dic3);

//根据key获取value
NSLog(@"key3 value :%@", [dic3 objectForKey:@"key3"]);

//获取字典数量
NSLog(@"dic count :%d", dic3.count);

//所有的键集合
NSArray *keys = [dic3 allKeys];
NSLog(@"keys :%@", keys);

//所有值集合
NSArray *values = [dic3 allValues];
NSLog(@"values :%@", values);

NSMutableDictionary *mutableDic = [[NSMutableDictionary alloc] initWithObjectsAndKeys:
@"mvalue1", @"mkey1",
@"mvalue2", @"mkey2", nil];
//添加现有的字典数据
[mutableDic addEntriesFromDictionary:dic3];
NSLog(@"mutableDic :%@",mutableDic);

//添加新的键值对象
[mutableDic setValue:@"set1" forKey:@"setKey1"];
NSLog(@"set value for key :%@",mutableDic);

//以新的字典数据覆盖旧的字典数据
[mutableDic setDictionary:dic2];
NSLog(@" set dictionary :%@",mutableDic);

//根据key删除value
[mutableDic removeObjectForKey:@"key1"];
NSLog(@"removeForkey :%@",mutableDic);

//快速遍历
for(id key in mutableDic) {
NSLog(@"key :%@  value :%@", key, [mutableDic objectForKey:key]);
}

//枚举遍历
NSEnumerator *enumerator = [mutableDic keyEnumerator];
id key = [enumerator nextObject];
while (key) {
NSLog(@"enumerator :%@", [mutableDic objectForKey:key]);
key = [enumerator nextObject];
}

//根据key数组删除元素
[mutableDic removeObjectsForKeys:keys];
NSLog(@"removeObjectsForKeys :%@",mutableDic);

[mutableDic removeAllObjects];
//删除所有元素
NSLog(@"remove all :%@", mutableDic);
}
return 0;
}

<pre name="code" class="html"> dic1 :{
key = value;
}
dic2 :{
key1 = value1;
key2 = value2;
key3 = value3;
key4 = value4;
}
dic3 :{
key1 = value1;
key2 = value2;
key3 = value3;
key4 = value4;
}
key3 value :value3
dic count :4
keys :(
key2,
key3,
key1,
key4
)
values :(
value2,
value3,
value1,
value4
)
mutableDic :{
key1 = value1;
key2 = value2;
key3 = value3;
key4 = value4;
mkey1 = mvalue1;
mkey2 = mvalue2;
}
set value for key :{
key1 = value1;
key2 = value2;
key3 = value3;
key4 = value4;
mkey1 = mvalue1;
mkey2 = mvalue2;
setKey1 = set1;
}
set dictionary :{
key1 = value1;
key2 = value2;
key3 = value3;
key4 = value4;
}
removeForkey :{
key2 = value2;
key3 = value3;
key4 = value4;
}
key :key4  value :value4
key :key2  value :value2
key :key3  value :value3
enumerator :value4
enumerator :value2
enumerator :value3
removeObjectsForKeys :{
}
remove all :{
}