是否有 NSMutableDictionary 文字语法来删除元素? [英] Is there NSMutableDictionary literal syntax to remove an element?

问题描述

在 NSMutableDictionary 中有添加对象和更改对象的字面语法，是否有删除对象的字面语法?

There is a literal syntax to add object and change object in an NSMutableDictionary, is there a literal syntax to remove object?

推荐答案

是的，但是... :-)

Yes, but... :-)

默认情况下不支持此功能，但是用于设置字典元素的新语法使用方法 setObject:forKeyedSubscript: 而不是 setObject:forKey:.因此，您可以编写一个类别来替换前者并设置或删除元素:

This is not supported by default, however the new syntax for setting dictionary elements uses the method setObject:forKeyedSubscript: rather than setObject:forKey:. So you can write a category which replaces the former and either sets or removes the element:

@implementation NSMutableDictionary (RemoveWithNil)

- (void) setObject:(id)obj forKeyedSubscript:(id<NSCopying>)key
{
   if (obj)
      [self setObject:obj forKey:key];
   else
      [self removeObjectForKey:key];
}

@end

将其添加到您的应用程序中，然后:

Add that to your application and then:

dict[aKey] = nil;

将删除一个元素.

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