keyEnumerator
Returns an enumerator object that lets you access each key in the dictionary.
- (NSEnumerator *)keyEnumerator
Return Value
An enumerator object that lets you access each key in the dictionary.
Discussion of [NSDictionary keyEnumerator]
The following code fragment illustrates how you might use this method.
NSEnumerator *enumerator = [myDictionary keyEnumerator];
|
id key;
|
|
while ((key = [enumerator nextObject])) {
|
/* code that uses the returned key */
|
}
|
If you use this method with instances of mutable subclasses of
NSDictionary, your code should not modify the entries during enumeration. If you intend to modify the entries, use the allKeys method to create a “snapshot” of the dictionary’s keys. Then use this snapshot to traverse the entries, modifying them along the way.
Note that the
objectEnumerator method provides a convenient way to access each value in the dictionary.Special Considerations
It is more efficient to use the fast enumeration protocol (see
NSFastEnumeration). Fast enumeration is available on OS X v10.5 and later and iOS 2.0 and later.
Example of [NSDictionary keyEnumerator]
NSEnumerator *enumerator = [myDictionary keyEnumerator];
for(NSString *aKey in enumerator) {
NSLog(@"%@", aKey);
NSLog(@"%@", [[myDictionary valueForKey:aKey] string]); //made up method
}
Example of [NSDictionary keyEnumerator]
id aKey = nil;
NSEnumerator *keyEnumerator = [paramaters keyEnumerator];
NSEnumerator *objectEnumerator = [paramaters objectEnumerator];
while ( (aKey = [keyEnumerator nextObject]) != nil) {
id value = [objectEnumerator nextObject];
NSLog(@"%@: %@", aKey, value);
}
Example of [NSDictionary keyEnumerator]
NSDictionary *myDict = ... some keys and values ...
NSEnumerator *keyEnum = [myDict keyEnumerator];
id key;
while ((key = [keyEnum nextObject]))
{
id value = [myDict objectForKey:key];
... do work with "value" ...
}