NSMutableDictionary在關鍵路徑中刪除對象？

Question

我有一個分層的NSMutableDictionary對象，我希望能夠刪除層次結構中更深層的字典。有沒有一個快速簡單的方法來做到這一點，例如，一個類似removeObjectAtKeyPath的方法？似乎無法找到一個。

謝謝！

Answer 1

沒有內置的，但你的基本範疇方法做得很好：

@implementation NSMutableDictionary (WSSNestedMutableDictionaries) 

- (void)WSSRemoveObjectForKeyPath: (NSString *)keyPath 
{ 
    // Separate the key path 
    NSArray * keyPathElements = [keyPath componentsSeparatedByString:@"."]; 
    // Drop the last element and rejoin the path 
    NSUInteger numElements = [keyPathElements count]; 
    NSString * keyPathHead = [[keyPathElements subarrayWithRange:(NSRange){0, numElements - 1}] componentsJoinedByString:@"."]; 
    // Get the mutable dictionary represented by the path minus that last element 
    NSMutableDictionary * tailContainer = [self valueForKeyPath:keyPathHead]; 
    // Remove the object represented by the last element 
    [tailContainer removeObjectForKey:[keyPathElements lastObject]]; 
} 

@end 

N.B.這要求該路徑倒數第二個元素 - tailContainer是響應removeObjectForKey:，可能是另一個NSMutableDictionary。如果不是，繁榮！

Answer 2

您可以創建一個類別：

這是高達1級下調：

#import "NSMutableDictionary+RemoveAtKeyPath.h" 

@implementation NSMutableDictionary (RemoveAtKeyPath) 

-(void)removeObjectAtKeyPath:(NSString *)keyPath{ 

    NSArray *paths=[keyPath componentsSeparatedByString:@"."]; 

    [[self objectForKey:paths[0]] removeObjectForKey:paths[1]]; 

} 

@end 

它被稱爲：

NSMutableDictionary *adict=[[NSMutableDictionary alloc]initWithDictionary:@{@"key1" : @"obj1", @"key11":@"obj11"}]; 

NSMutableDictionary *bdict=[[NSMutableDictionary alloc]initWithDictionary:@{@"key2" : adict}]; 

NSLog(@"%@",bdict); 
NSLog(@"%@",[bdict valueForKeyPath:@"key2.key1"]); 

[bdict removeObjectAtKeyPath:@"key2.key1"]; 
NSLog(@"After category : %@",bdict); 

Answer 3

輕微改善，Josh的答案，以處理不包含句keypaths（即keypaths這實際上鍵）：

- (void)removeObjectAtKeyPath:(NSString *)keyPath 
{ 
    NSArray *keyPathElements = [keyPath componentsSeparatedByString:@"."]; 
    NSUInteger numElements = [keyPathElements count]; 
    if (numElements == 1) { 
     [self removeObjectForKey:keyPath]; 
    } else { 
     NSString *keyPathHead = [[keyPathElements subarrayWithRange:(NSRange){0, numElements - 1}] componentsJoinedByString:@"."]; 
     NSMutableDictionary *tailContainer = [self valueForKeyPath:keyPathHead]; 
     [tailContainer removeObjectForKey:[keyPathElements lastObject]]; 
    } 
} 

Answer 4

我知道這是一個較舊的職位，但我需要發現雨燕2.0相同的解決方案，無法找到一個簡單的答案，我想出了這個解決方案：

public extension NSMutableDictionary { 
    public func removeObjectAtKeyPath(keyPath:String) { 
     let elements = keyPath.componentsSeparatedByString(".") 
     let head = elements.first! 
     if elements.count > 1 { 
      let tail = elements[1...elements.count-1].joinWithSeparator(".") 
      if let d = valueForKeyPath(head) as? NSMutableDictionary { 
       d.removeObjectAtKeyPath(tail) 
      } 
     }else{ 
      removeObjectForKey(keyPath) 
     } 
    } 
} 

我使用遞歸步驟通的keyPath

添加一個擴展到