NSDictionary的使用

r囧r小猫 2021-12-20 14:59 145阅读 0赞

通过唯一的key找到对应的value,类似于Java中的Map

**创建NSDictionary的方法**

*  \+ (id)dictionary
 *  \+ (id)dictionaryWithObject:(id)object forKey:(id<NSCopying>)key //作为key的对象需实现NSCopying协议
 *  \+ (id)dictionaryWithObjectsAndKeys:(id)firstObject,... //key和Object需成功出 , 如: NSDictionary \*dict = \[NSDictionary dictionaryWithObjectsAndKeys: @"v1", @"k1",@"v2",@"k2",nil\]
 *  \+ (id)dictionaryWithDictionary:(NSDictionary \*)dict
 *  \+ (id)dictionaryWithObjects:(NSArray \*)objects forKeys:(NSArray \*)keys
 *  \- (id)initWithObjectsAndKeys:(id)firstObject,...
 *  \- (id)initWithDictionary:(NSDictionary \*)otherDictionary
 *  \- (id)initWithObjects:(NSArray \*)objects forKeys:(NSArray \*)keys
 *  \+ (id)dictionaryWithContentsOfFile:(NSString \*)path
 *  \+ (id)dictionaryWithContentsOfURL:(NSURL \*)url
 *  \- (id)initWithContentsOfFile:(NSString \*)path
 *  \- (id)initWithContentsOfURL:(NSURL \*)url

**NSDictionary常用方法**

*  \- (NSUInteger) count //返回字典的key数
 *  \- (BOOL)isEqualToDictionary:(NSDictionary \*)otherDictionary //比较两个字典
 *  \- (BOOL)writeToFile:(NSString \*)path atomically:(BOOL)useAuxiliaryFile //将一个NSDictionary持久化到文件中去

**NSDictionary访问key和value**

*  \- (NSArray \*)allKeys //返回所有的key
 *  \- (NSArray \*)allKeysForObject:(id)anObject //返回anObject元素对应的所有key
 *  \- (NSArray \*)allValues //返回所有的value
 *  \- (id)objectForKey:(id)aKey //根据aKey返回对应的value
 *  \- (NSArray \*)objectsForKeys:(NSArray \*)keys notFoundMarker:(id)marker //返回keys对应的所有value, 如果没有对应的value, 用marker代替

**NSDictionary遍历**

*  快速遍历: for (NSString \*key in dict)
 *  迭代器遍历:
    
     *  \- (NSEnumerator \*)keyEnumerator //key的迭代器
     *  \- (NSEnumerator \*)objectEnumerator //value的迭代器
 *  block遍历 \[dict enumeratorKeysAndObjectsUsingBlock:^(id key, id object, BOOL \*stop)\{ NSLog(@"key=%@, object=%@", key, object); \}\];

**NSDictionary的key排序**

*  \- (NSArray \*)keyssortedByValueUsingComparator:(NSComparator)cmptr
 *  \- (NSArray \*)keysSortedByValueWithOptions:(NSSortOptions)opts usingComparator:(NSComparator)cmptr
 *  \- (NSArray \*)keysSortedByValueUsingSelector:(SEL)comparator

转载于:https://www.cnblogs.com/martinhu/p/3868024.html