ios 循环遍历 NSMutableDictionary
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looping through an NSMutableDictionary
提问by Rupert
How do I loop through all objects in a NSMutableDictionary regardless of the keys?
无论键如何，如何遍历 NSMutableDictionary 中的所有对象？
回答by Henrik P. Hessel
A standard way would look like this
一个标准的方式看起来像这样
for(id key in myDict) {
id value = [myDict objectForKey:key];
[value doStuff];
}
回答by Andrey Zverev
you can use
您可以使用
[myDict enumerateKeysAndObjectsUsingBlock: ^(id key, id obj, BOOL *stop) {
// do something with key and obj
}];
if your target OS supports blocks.
如果您的目标操作系统支持块。
回答by jv42
You can use [dict allValues]to get an NSArrayof your values. Be aware that it doesn't guarantee any order between calls.
您可以使用[dict allValues]来获取NSArray您的值。请注意，它不保证调用之间的任何顺序。
回答by user3540599
- For simple loop, fast enumeration is a bit faster than block-based loop
- It's easier to do concurrent or reverse enumeration with block-based enumeration than with fast enumeration When looping with NSDictionary you can get key and value in one hit with a block-based enumerator, whereas with fast enumeration you have to use the key to retrieve the value in a separate message send
- 对于简单循环，快速枚举比基于块的循环快一点
- 使用基于块的枚举进行并发或反向枚举比使用快速枚举更容易使用 NSDictionary 进行循环时，您可以使用基于块的枚举器一次性获得键和值，而使用快速枚举则必须使用键来检索单独消息发送中的值
in fast enumeration
在快速枚举中
for(id key in myDictionary) {
id value = [myDictionary objectForKey:key];
// do something with key and obj
}
in Blocks :
在块中：
[myDictionary enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
// do something with key and obj
}];
回答by Alexander
You don't need to assign value to a variable. You can access it directly with myDict[key].
您不需要为变量赋值。您可以直接使用myDict[key].
for(id key in myDict) {
NSLog(@"Key:%@ Value:%@", key, myDict[key]);
}
回答by Hendrik
Another way is to use the Dicts Enumerator. Here is some sample code from Apple:
另一种方法是使用 Dicts Enumerator。以下是来自 Apple 的一些示例代码：
NSEnumerator *enumerator = [myDictionary objectEnumerator];
id value;
while ((value = [enumerator nextObject])) {
/* code that acts on the dictionary's values */
}
