Looping in NSMutableDictionary

Question

How do I scroll all objects in an NSMutableDictionary regardless of keys?

Answer 1

The standard way would look like this:

for(id key in myDict) { id value = [myDict objectForKey:key]; [value doStuff]; } 

Answer 2

you can use

 [myDict enumerateKeysAndObjectsUsingBlock: ^(id key, id obj, BOOL *stop) { // do something with key and obj }]; 

if your target OS supports blocks.

Answer 3

You can use [dict allValues] to get the NSArray your values. Keep in mind that it does not guarantee any order between calls.

Answer 4

You do not need to assign a value to a variable. You can access it directly with myDict[key] .

  for(id key in myDict) { NSLog(@"Key:%@ Value:%@", key, myDict[key]); } 

Answer 5

• For a simple loop, fast enumeration is slightly faster than a block-based loop
• It is easier to perform parallel or backward enumeration using block enumeration than with fast enumeration. When cyclized with NSDictionary, you can get the key and value in one hit with the enumerator block, while with fast enumeration you must use the key to retrieve the value in a separate message.

in quick listing

 for(id key in myDictionary) { id value = [myDictionary objectForKey:key]; // do something with key and obj } 

in blocks:

 [myDictionary enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) { // do something with key and obj }]; 

Answer 6

Another way is to use the Dicts Enumerator. Here is a sample code from Apple:

 NSEnumerator *enumerator = [myDictionary objectEnumerator]; id value; while ((value = [enumerator nextObject])) { /* code that acts on the dictionary's values */ }