looping through an NSMutableDictionary
Objective CIosNsmutabledictionaryObjective C Problem Overview
How do I loop through all objects in a NSMutableDictionary regardless of the keys?
Objective C Solutions
Solution 1 - Objective C
A standard way would look like this
for(id key in myDict) {
id value = [myDict objectForKey:key];
[value doStuff];
}
Solution 2 - Objective C
you can use
[myDict enumerateKeysAndObjectsUsingBlock: ^(id key, id obj, BOOL *stop) {
// do something with key and obj
}];
if your target OS supports blocks.
Solution 3 - Objective C
You can use [dict allValues]
to get an NSArray
of your values. Be aware that it doesn't guarantee any order between calls.
Solution 4 - Objective C
- 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
in fast enumeration
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
}];
Solution 5 - Objective C
You don't need to assign value to a variable. You can access it directly with myDict[key]
.
for(id key in myDict) {
NSLog(@"Key:%@ Value:%@", key, myDict[key]);
}
Solution 6 - Objective C
Another way is to use the Dicts Enumerator. Here is some sample code from Apple:
NSEnumerator *enumerator = [myDictionary objectEnumerator];
id value;
while ((value = [enumerator nextObject])) {
/* code that acts on the dictionary’s values */
}