Question

我正在尝试检查xcode中plist文件中是否存在密钥。我的plist文件有这种结构。

Root (Dictionary)
+- Parent1 (Dictionary)
   - Key1 (Boolean)
   - Key2 (Boolean)
   - Key3 (Boolean)
   - Key4 (Boolean)

+- Parent2 (Dictionary)
   - Key1 (Boolean)
   - Key2 (Boolean)

现在我需要检查在Parent1中是否存在Key2？我检查了NSDictionary，但无法知道如何做到这一点。

有关如何执行此操作的任何建议吗？

Answer 1

 NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:@"your.plist"];
 BOOL key2Exists = [[dict objectForKey:@"Parent1"] objectForKey:@"Key2"] != nil;

对于显式nil比较，我有时会使用它，因为它使代码对我来说更具可读性（它提醒我语句左侧的变量是布尔值）。我也看过一个明确的“布尔演员”：

BOOL key2Exists = !![[dict objectForKey:@"Parent1"] objectForKey:@"Key2"];

我想这是个人偏好的问题。

Answer 2

NSDictionary *dictionary = [NSDictionary dictionaryWithContentsOfFile:@"some.plist"];
NSDictionary *parentDictionary = [dictionary objectForKey:@"Parent1"];

NSSet *allKeys = [NSSet arrayWithSet:[parentDictionary allKeys]];
BOOL keyExists = [allKeys containsObject:@"Key2"];

如何检查plist中是否存在键？

2 个答案: