API之NSDictionary的常見用法

/*

NSDictionary *dic1 = [[NSDictionary alloc]

initWithObjectsAndKeys:@"李四", @"name", @"不明",@"gender", nil];

//字典中的對象可以重複存儲

//71 - (instancetype)initWithObjectsAndKeys:(id)firstObject, ...

NSDictionary *dic2 = [[NSDictionary alloc] initWithObjectsAndKeys:@"孫⼤大聖", @"name", @"孫⼤大聖",@"monkey", @"豬⼋八戒", @"貪喫⿁鬼", nil];

// NSLog(@"%@", [dic1objectForKey:@"name"]);

// NSLog(@"%@", dic1); //打印UTF8編碼一個UTF8是兩個字節

// //把所有key作爲數組輸出

// NSArray *keys = [dic1 allKeys];

//

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

// NSLog(@"%@ : %@", keys[i], dic1[keys[i]]);

// }

// //輸出同一對象的所有下標

// NSLog(@"%@", [dic2allKeysForObject:@"sun"]);

// //獲取字典⾥裏所有元素

// NSArray *array1 = [dic1 allValues];

// NSLog(@"%@", array1);

// //判斷兩個數組是否相等

// if ([dic1 isEqualToDictionary:dic2]) {

// NSLog(@"yes");

// } else {

// NSLog(@"no");

// }

*/

/*

//72 - (instancetype)initWithDictionary:

(NSDictionary *)otherDictionary;

NSDictionary *dic3 = [[NSDictionary alloc]

initWithDictionary:dic2];

NSLog(@"%@", dic3);

//87 - (void)removeObjectForKey:(id)aKey;

NSArray *key2 = [dic2 allKeys];

*/

//可變字典

NSMutableDictionary *mDic1=

[[NSMutableDictionaryalloc] initWithObjectsAndKeys:@"多啦A夢",@"name", @"百變⼝口袋", @"skill", nil];

NSArray *keys1= [mDic1 allKeys];

for (int i = 0; i <[keys1 count]; i++) {

NSLog(@"%@ : %@", [keys1objectAtIndex:i],

[mDic1 objectForKey:[keys1 objectAtIndex:i]]);

}

//通過key移除對象

// [mDic1 removeObjectForKey:@"name"];

// NSLog(@"%@", [mDic1objectForKey:@"name"]);

NSMutableDictionary *mDic2=[[NSMutableDictionaryalloc]init];

//把後⾯面的字典拷⻉貝給前⾯面的字典

[mDic2 setDictionary:mDic1];

// NSArray *key2 = [mDic2 allKeys];

// for (int i = 0; i < [key2 count]; i++) {

// NSLog(@"%@ : %@", [key2 objectAtIndex:i],

[mDic2 objectForKey:[key2 objectAtIndex:i]]);

// }

//重新寫⼊入key所保存的對象

[mDic2 setObject:@"⼤大熊"forKey:@"name"];

NSArray *key2= [mDic2 allKeys];

for (int i = 0; i< [key2 count]; i++) {

NSLog(@"%@ : %@", [key2objectAtIndex:i],

[mDic2 objectForKey:[key2 objectAtIndex:i]]);

}

//88 - (void)setObject:(id)anObject forKey:(id

<NSCopying>)aKey; 空指針相當於上⾯面的代碼