NSSet
来源:互联网 发布:cms监控软件怎么用 编辑:程序博客网 时间:2024/05/05 14:23
Next
Overview
The NSSet, NSMutableSet, and NSCountedSet classes declare the programmatic interface to an unordered collection of objects.
NSSet declares the programmatic interface for static sets of distinct objects. You establish a static set’s entries when it’s created, and thereafter the entries can’t be modified.NSMutableSet, on the other hand, declares a programmatic interface for dynamic sets of distinct objects. A dynamic—or mutable—set allows the addition and deletion of entries at any time, automatically allocating memory as needed.
You can use sets as an alternative to arrays when the order of elements isn’t important and performance in testing whether an object is contained in the set is a consideration—while arrays are ordered, testing for membership is slower than with sets.
NSSet is “toll-free bridged” with its Core Foundation counterpart,CFSetRef. See “Toll-Free Bridging” for more information on toll-free bridging.
Subclassing Notes
There should be little need of subclassing. If you need to customize behavior, it is often better to consider composition instead of subclassing.
Methods to Override
In a subclass, you must override all of its primitive methods:
- count
- member:
- objectEnumerator
Alternatives to Subclassing
Before making a custom class of NSSet, investigateNSHashTable and the corresponding Core Foundation type,CFSet Reference. Because NSSet andCFSet are “toll-free bridged,” you can substitute a CFSet object for a NSSet object in your code (with appropriate casting). Although they are corresponding types,CFSet and NSSet do not have identical interfaces or implementations, and you can sometimes do things withCFSet that you cannot easily do with NSSet.
If the behavior you want to add supplements that of the existing class, you could write a category onNSSet. Keep in mind, however, that this category will be in effect for all instances ofNSSet that you use, and this might have unintended consequences. Alternatively, you could use composition to achieve the desired behavior.
Adopted Protocols
NSCoding
- encodeWithCoder:
- initWithCoder:
NSCopying
- copyWithZone:
NSMutableCopying
- mutableCopyWithZone:
NSFastEnumeration
- countByEnumeratingWithState:objects:count:
Tasks
Creating a Set
- + set
- + setWithArray:
- + setWithObject:
- + setWithObjects:
- + setWithObjects:count:
- + setWithSet:
- – setByAddingObject:
- – setByAddingObjectsFromSet:
- – setByAddingObjectsFromArray:
Initializing a Set
- – initWithArray:
- – initWithObjects:
- – initWithObjects:count:
- – initWithSet:
- – initWithSet:copyItems:
- – init
Counting Entries
- – count
Accessing Set Members
- – allObjects
- – anyObject
- – containsObject:
- – filteredSetUsingPredicate:
- – makeObjectsPerformSelector:
- – makeObjectsPerformSelector:withObject:
- – member:
- – objectEnumerator
- – enumerateObjectsUsingBlock:
- – enumerateObjectsWithOptions:usingBlock:
- – objectsPassingTest:
- – objectsWithOptions:passingTest:
Comparing Sets
- – isSubsetOfSet:
- – intersectsSet:
- – isEqualToSet:
- – valueForKey:
- – setValue:forKey:
Creating a Sorted Array
- – sortedArrayUsingDescriptors:
Key-Value Observing
- – addObserver:forKeyPath:options:context:
- – removeObserver:forKeyPath:context:
- – removeObserver:forKeyPath:
Describing a Set
- – description
- – descriptionWithLocale:
Class Methods
set
Creates and returns an empty set.
+ (instancetype)set
Return Value
A new empty set.
Discussion
This method is declared primarily for the use of mutable subclasses ofNSSet.
Availability
- Available in OS X v10.0 and later.
See Also
- + setWithArray:
- + setWithObject:
- + setWithObjects:
- – setByAddingObject:
- – setByAddingObjectsFromSet:
- – setByAddingObjectsFromArray:
Related Sample Code
- RemoteCurrency
- TreeView
Declared In
NSSet.h
setWithArray:
Creates and returns a set containing a uniqued collection of the objects contained in a given array.
+ (instancetype)setWithArray:(NSArray *)array
Parameters
array
An array containing the objects to add to the new set. If the same object appears more than once in array, it is added only once to the returned set. Each object receives aretain message as it is added to the set.
Return Value
A new set containing a uniqued collection of the objects contained in array.
Availability
- Available in OS X v10.0 and later.
See Also
- + set
- + setWithObject:
- + setWithObjects:
- – setByAddingObject:
- – setByAddingObjectsFromSet:
- – setByAddingObjectsFromArray:
Related Sample Code
- Writing Subtitles to a Movie from the Command Line for OS X
Declared In
NSSet.h
setWithObject:
Creates and returns a set that contains a single given object.
+ (instancetype)setWithObject:(id)object
Parameters
object
The object to add to the new set. object receives a retain message after being added to the set.
Return Value
A new set that contains a single member, object.
Availability
- Available in OS X v10.0 and later.
See Also
- + set
- + setWithArray:
- + setWithObjects:
- – setByAddingObject:
- – setByAddingObjectsFromSet:
- – setByAddingObjectsFromArray:
Related Sample Code
- AnimatedTableView
- PictureSharing
- Sketch
- Sketch+Accessibility
- TreeView
Declared In
NSSet.h
setWithObjects:
Creates and returns a set containing the objects in a given argument list.
+ (instancetype)setWithObjects:(id)firstObj,...
Parameters
firstObj
The first object to add to the new set.
firstObj, ...
A comma-separated list of objects, ending with nil, to add to the new set. If the same object appears more than once in the list of objects, it is added only once to the returned set. Each object receives aretain message as it is added to the set.
Return Value
A new set containing the objects in the argument list.
Discussion
As an example, the following code excerpt creates a set containing three different types of elements (assumingaPath exits):
NSSet *mySet;
NSData *someData = [NSData dataWithContentsOfFile:aPath];
NSValue *aValue = [NSNumber numberWithInteger:5];
NSString *aString = @"a string";
mySet = [NSSet setWithObjects:someData, aValue, aString, nil];
Availability
- Available in OS X v10.0 and later.
See Also
- + set
- + setWithArray:
- + setWithObject:
- – setByAddingObject:
- – setByAddingObjectsFromSet:
- – setByAddingObjectsFromArray:
Related Sample Code
- AVRecorder
- iSpend
- QTRecorder
- Sketch
- Sketch+Accessibility
Declared In
NSSet.h
setWithObjects:count:
Creates and returns a set containing a specified number of objects from a given C array of objects.
+ (instancetype)setWithObjects:(const id [])objects count:(NSUInteger)cnt
Parameters
objects
A C array of objects to add to the new set. If the same object appears more than once in objects, it is added only once to the returned set. Each object receives aretain message as it is added to the set.
cnt
The number of objects from objects to add to the new set.
Return Value
A new set containing cnt objects from the list of objects specified by objects.
Availability
- Available in OS X v10.0 and later.
See Also
- + set
- + setWithArray:
- + setWithObject:
- + setWithObjects:
- – setByAddingObject:
- – setByAddingObjectsFromSet:
- – setByAddingObjectsFromArray:
Declared In
NSSet.h
setWithSet:
Creates and returns a set containing the objects from another set.
+ (instancetype)setWithSet:(NSSet *)set
Parameters
set
A set containing the objects to add to the new set. Each object receives aretain message as it is added to the new set.
Return Value
A new set containing the objects from set.
Availability
- Available in OS X v10.0 and later.
See Also
- + set
- + setWithArray:
- + setWithObject:
- + setWithObjects:
- – setByAddingObject:
- – setByAddingObjectsFromSet:
- – setByAddingObjectsFromArray:
Declared In
NSSet.h
Instance Methods
addObserver:forKeyPath:options:context:
Raises an exception.
- (void)addObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options context:(void *)context
Parameters
observer
The object to register for KVO notifications. The observer must implement the key-value observing methodobserveValueForKeyPath:ofObject:change:context:.
keyPath
The key path, relative to the set, of the property to observe. This value must not benil.
options
A combination of the NSKeyValueObservingOptions values that specifies what is included in observation notifications. For possible values, seeNSKeyValueObservingOptions.
context
Arbitrary data that is passed to observer in observeValueForKeyPath:ofObject:change:context:.
Special Considerations
NSSet objects are not observable, so this method raises an exception when invoked on anNSSet object. Instead of observing a set, observe the unordered to-many relationship for which the set is the collection of related objects.
Availability
- Available in OS X v10.4 and later.
See Also
- – removeObserver:forKeyPath:
Declared In
NSKeyValueObserving.h
allObjects
Returns an array containing the set’s members, or an empty array if the set has no members.
- (NSArray *)allObjects
Return Value
An array containing the set’s members, or an empty array if the set has no members. The order of the objects in the array isn’t defined.
Availability
- Available in OS X v10.0 and later.
See Also
- – anyObject
- – objectEnumerator
Related Sample Code
- LightTable
Declared In
NSSet.h
anyObject
Returns one of the objects in the set, or nil if the set contains no objects.
- (id)anyObject
Return Value
One of the objects in the set, or nil if the set contains no objects. The object returned is chosen at the set’s convenience—the selection is not guaranteed to be random.
Availability
- Available in OS X v10.0 and later.
See Also
- – allObjects
- – objectEnumerator
Related Sample Code
- TreeView
Declared In
NSSet.h
containsObject:
Returns a Boolean value that indicates whether a given object is present in the set.
- (BOOL)containsObject:(id)anObject
Parameters
anObject
The object for which to test membership of the set.
Return Value
YES if anObject is present in the set, otherwiseNO.
Availability
- Available in OS X v10.0 and later.
See Also
- – member:
Related Sample Code
- OpenGL Filter Basics Cocoa
Declared In
NSSet.h
count
Returns the number of members in the set.
- (NSUInteger)count
Return Value
The number of members in the set.
Availability
- Available in OS X v10.0 and later.
Related Sample Code
- LightTable
Declared In
NSSet.h
description
Returns a string that represents the contents of the set, formatted as a property list.
- (NSString *)description
Return Value
A string that represents the contents of the set, formatted as a property list.
Availability
- Available in OS X v10.0 and later.
See Also
- – descriptionWithLocale:
Declared In
NSSet.h
descriptionWithLocale:
Returns a string that represents the contents of the set, formatted as a property list.
- (NSString *)descriptionWithLocale:(id)locale
Parameters
locale
On iOS and OS X v10.5 and later, either an instance of NSDictionary or an NSLocale object may be used for locale.On OS X v10.4 and earlier it must be an instance ofNSDictionary.
Return Value
A string that represents the contents of the set, formatted as a property list.
Discussion
This method sends each of the set’s members descriptionWithLocale: with locale passed as the sole parameter. If the set’s members do not respond todescriptionWithLocale:, this method sends description instead.
Availability
- Available in OS X v10.0 and later.
See Also
- – description
Declared In
NSSet.h
enumerateObjectsUsingBlock:
Executes a given Block using each object in the set.
- (void)enumerateObjectsUsingBlock:(void (^)(id obj, BOOL *stop))block
Parameters
block
The Block to apply to elements in the set.
The Block takes two arguments:
obj
The element in the set.
stop
A reference to a Boolean value. The block can set the value to YES to stop further processing of the set. The stop argument is an out-only argument. You should only ever set this Boolean to YES within the Block.
The Block returns a Boolean value that indicates whether obj passed the test.
Availability
- Available in OS X v10.6 and later.
Declared In
NSSet.h
enumerateObjectsWithOptions:usingBlock:
Executes a given Block using each object in the set, using the specified enumeration options.
- (void)enumerateObjectsWithOptions:(NSEnumerationOptions)opts usingBlock:(void (^)(id obj, BOOL *stop))block
Parameters
opts
A bitmask that specifies the options for the enumeration.
block
The Block to apply to elements in the set.
The Block takes two arguments:
obj
The element in the set.
stop
A reference to a Boolean value. The block can set the value to YES to stop further processing of the set. The stop argument is an out-only argument. You should only ever set this Boolean to YES within the Block.
The Block returns a Boolean value that indicates whether obj passed the test.
Availability
- Available in OS X v10.6 and later.
Declared In
NSSet.h
filteredSetUsingPredicate:
Evaluates a given predicate against each object in the receiving set and returns a new set containing the objects for which the predicate returns true.
- (NSSet *)filteredSetUsingPredicate:(NSPredicate *)predicate
Parameters
predicate
A predicate.
Return Value
A new set containing the objects in the receiving set for which predicate returns true.
Discussion
The following example illustrates the use of this method.
NSSet *sourceSet =
[NSSet setWithObjects:@"One", @"Two", @"Three", @"Four", nil];
NSPredicate *predicate =
[NSPredicate predicateWithFormat:@"SELF beginswith 'T'"];
NSSet *filteredSet =
[sourceSet filteredSetUsingPredicate:predicate];
// filteredSet contains (Two, Three)
Availability
- Available in OS X v10.5 and later.
Declared In
NSPredicate.h
init
Initializes a newly allocated set.
- (instancetype)init
Return Value
A set.
Discussion
This method is a designated initializer of NSSet.
Availability
- Available in OS X v10.9 and later.
See Also
- – initWithObjects:count:
Declared In
NSSet.h
initWithArray:
Initializes a newly allocated set with the objects that are contained in a given array.
- (instancetype)initWithArray:(NSArray *)array
Parameters
array
An array of objects to add to the new set. If the same object appears more than once in array, it is represented only once in the returned set. Each object receives aretain message as it is added to the set.
Return Value
An initialized set with the contents of array. The returned set might be different than the original receiver.
Availability
- Available in OS X v10.0 and later.
See Also
- – initWithObjects:
- – initWithObjects:count:
- – initWithSet:
- – initWithSet:copyItems:
- – init
- + setWithArray:
Declared In
NSSet.h
initWithObjects:
Initializes a newly allocated set with members taken from the specified list of objects.
- (instancetype)initWithObjects:(id)firstObj,...
Parameters
firstObj
The first object to add to the new set.
firstObj, ...
A comma-separated list of objects, ending with nil, to add to the new set. If the same object appears more than once in the list, it is represented only once in the returned set. Each object receives aretain message as it is added to the set
Return Value
An initialized set containing the objects specified in the parameter list. The returned set might be different than the original receiver.
Availability
- Available in OS X v10.0 and later.
See Also
- – initWithArray:
- – initWithObjects:count:
- – initWithSet:
- – initWithSet:copyItems:
- – init
- + setWithObjects:
Declared In
NSSet.h
initWithObjects:count:
Initializes a newly allocated set with a specified number of objects from a given C array of objects.
- (instancetype)initWithObjects:(const id [])objects count:(NSUInteger)cnt
Parameters
objects
A C array of objects to add to the new set. If the same object appears more than once in objects, it is added only once to the returned set. Each object receives aretain message as it is added to the set.
cnt
The number of objects from objects to add to the new set.
Return Value
An initialized set containing cnt objects from the list of objects specified by objects. The returned set might be different than the original receiver.
Discussion
This method is a designated initializer for NSSet.
Availability
- Available in OS X v10.0 and later.
See Also
- – initWithArray:
- – initWithObjects:
- – initWithSet:
- – initWithSet:copyItems:
- – init
- + setWithObjects:count:
Declared In
NSSet.h
initWithSet:
Initializes a newly allocated set and adds to it objects from another given set.
- (instancetype)initWithSet:(NSSet *)set
Parameters
set
A set containing objects to add to the receiving set. Each object is retained as it is added.
Return Value
An initialized objects set containing the objects from set. The returned set might be different than the original receiver.
Availability
- Available in OS X v10.0 and later.
See Also
- – initWithArray:
- – initWithObjects:
- – initWithObjects:count:
- – initWithSet:copyItems:
- – init
- + setWithSet:
Declared In
NSSet.h
initWithSet:copyItems:
Initializes a newly allocated set and adds to it members of another given set.
- (instancetype)initWithSet:(NSSet *)set copyItems:(BOOL)flag
Parameters
set
A set containing objects to add to the new set.
flag
If YES, each object in set receives a copyWithZone: message to create a copy of the object—objects must conform to theNSCopying protocol. In a managed memory environment, this is instead of theretain message the object would otherwise receive. The object copy is then added to the returned set.
If NO, then in a managed memory environment each object in set simply receives aretain message when it is added to the returned set.
Return Value
An initialized set that contains the members of set. The returned set might be different than the original receiver.
Discussion
After an immutable s has been initialized in this way, it cannot be modified.
The copyWithZone: method performs a shallow copy. If you have a collection of arbitrary depth, passingYES for the flag parameter will perform an immutable copy of the first level below the surface. If you passNO the mutability of the first level is unaffected. In either case, the mutability of all deeper levels is unaffected.
Availability
- Available in OS X v10.0 and later.
See Also
- – initWithArray:
- – initWithObjects:
- – initWithObjects:count:
- – initWithSet:
- – init
- + setWithSet:
Declared In
NSSet.h
intersectsSet:
Returns a Boolean value that indicates whether at least one object in the receiving set is also present in another given set.
- (BOOL)intersectsSet:(NSSet *)otherSet
Parameters
otherSet
The set with which to compare the receiving set.
Return Value
YES if at least one object in the receiving set is also present in otherSet, otherwiseNO.
Discussion
Object equality is tested using isEqual:.
Availability
- Available in OS X v10.0 and later.
See Also
- – isEqualToSet:
- – isSubsetOfSet:
Declared In
NSSet.h
isEqualToSet:
Compares the receiving set to another set.
- (BOOL)isEqualToSet:(NSSet *)otherSet
Parameters
otherSet
The set with which to compare the receiving set.
Return Value
YES if the contents of otherSet are equal to the contents of the receiving set, otherwiseNO.
Discussion
Two sets have equal contents if they each have the same number of members and if each member of one set is present in the other. Object equality is tested usingisEqual:.
Availability
- Available in OS X v10.0 and later.
See Also
- – intersectsSet:
- isEqual: (NSObject protocol)
- – isSubsetOfSet:
Declared In
NSSet.h
isSubsetOfSet:
Returns a Boolean value that indicates whether every object in the receiving set is also present in another given set.
- (BOOL)isSubsetOfSet:(NSSet *)otherSet
Parameters
otherSet
The set with which to compare the receiving set.
Return Value
YES if every object in the receiving set is also present in otherSet, otherwiseNO.
Discussion
Object equality is tested using isEqual:.
Availability
- Available in OS X v10.0 and later.
See Also
- – intersectsSet:
- – isEqualToSet:
Declared In
NSSet.h
makeObjectsPerformSelector:
Sends a message specified by a given selector to each object in the set.
- (void)makeObjectsPerformSelector:(SEL)aSelector
Parameters
aSelector
A selector that specifies the message to send to the members of the set. The method must not take any arguments. It should not have the side effect of modifying the set. This value must not beNULL.
Discussion
The message specified by aSelector is sent once to each member of the set. This method raises anNSInvalidArgumentException if aSelector is NULL.
Availability
- Available in OS X v10.0 and later.
See Also
- – makeObjectsPerformSelector:withObject:
Declared In
NSSet.h
makeObjectsPerformSelector:withObject:
Sends a message specified by a given selector to each object in the set.
- (void)makeObjectsPerformSelector:(SEL)aSelector withObject:(id)argument
Parameters
aSelector
A selector that specifies the message to send to the set's members. The method must take a single argument of typeid. The method should not, as a side effect, modify the set. The value must not beNULL.
argument
The object to pass as an argument to the method specified by aSelector.
Discussion
The message specified by aSelector is sent, with argument as the argument, once to each member of the set. This method raises anNSInvalidArgumentException if aSelector is NULL.
Availability
- Available in OS X v10.0 and later.
See Also
- – makeObjectsPerformSelector:
Declared In
NSSet.h
member:
Determines whether the set contains an object equal to a given object, and returns that object if it is present.
- (id)member:(id)object
Parameters
object
The object for which to test for membership of the set.
Return Value
If the set contains an object equal to object (as determined by isEqual:) then that object (typically this will be object), otherwisenil.
Discussion
If you override isEqual:, you must also override thehash method for the member: method to work on a set of objects of your class.
Availability
- Available in OS X v10.0 and later.
Declared In
NSSet.h
objectEnumerator
Returns an enumerator object that lets you access each object in the set.
- (NSEnumerator *)objectEnumerator
Return Value
An enumerator object that lets you access each object in the set.
Discussion
The following code fragment illustrates how you can use this method.
NSEnumerator *enumerator = [mySet objectEnumerator];
id value;
while ((value = [enumerator nextObject])) {
/* code that acts on the set’s values */
}
When this method is used with mutable subclasses of NSSet, your code shouldn’t modify the set during enumeration. If you intend to modify the set, use theallObjects method to create a “snapshot” of the set’s members. Enumerate the snapshot, but make your modifications to the original set.
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.
Availability
- Available in OS X v10.0 and later.
See Also
- nextObject (NSEnumerator)
Related Sample Code
- QuickLookSketch
- Sketch
- Sketch+Accessibility
Declared In
NSSet.h
objectsPassingTest:
Returns a set of object that pass a test in a given Block.
- (NSSet *)objectsPassingTest:(BOOL (^)(id obj, BOOL *stop))predicate
Parameters
predicate
The block to apply to elements in the array.
The block takes three arguments:
obj
The element in the set.
stop
A reference to a Boolean value. The block can set the value to YES to stop further processing of the set. The stop argument is an out-only argument. You should only ever set this Boolean to YES within the Block.
The Block returns a Boolean value that indicates whether obj passed the test.
Return Value
An NSSet containing objects that pass the test.
Availability
- Available in OS X v10.6 and later.
Declared In
NSSet.h
objectsWithOptions:passingTest:
Returns a set of object that pass a test in a given Block, using the specified enumeration options.
- (NSSet *)objectsWithOptions:(NSEnumerationOptions)opts passingTest:(BOOL (^)(id obj, BOOL *stop))predicate
Parameters
opts
A bitmask that specifies the options for the enumeration.
predicate
The Block to apply to elements in the set.
The Block takes two arguments:
obj
The element in the set.
stop
A reference to a Boolean value. The block can set the value to YES to stop further processing of the set. The stop argument is an out-only argument. You should only ever set this Boolean to YES within the Block.
The Block returns a Boolean value that indicates whether obj passed the test.
Return Value
An NSSet containing objects that pass the test.
Availability
- Available in OS X v10.6 and later.
Declared In
NSSet.h
removeObserver:forKeyPath:
Raises an exception.
- (void)removeObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath
Parameters
observer
The object to remove as an observer.
keyPath
A key-path, relative to the set, for which observer is registered to receive KVO change notifications. This value must not benil.
Special Considerations
NSSet objects are not observable, so this method raises an exception when invoked on anNSSet object. Instead of observing a set, observe the unordered to-many relationship for which the set is the collection of related objects.
Availability
- Available in OS X v10.4 and later.
See Also
- – addObserver:forKeyPath:options:context:
Declared In
NSKeyValueObserving.h
removeObserver:forKeyPath:context:
Raises an exception.
- (void)removeObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath context:(void *)context
Parameters
observer
The object to remove as an observer.
keyPath
A key-path, relative to the set, for which observer is registered to receive KVO change notifications. This value must not benil.
context
Arbitrary data that is passed to observer in observeValueForKeyPath:ofObject:change:context:.
Special Considerations
NSSet objects are not observable, so this method raises an exception when invoked on anNSSet object. Instead of observing a set, observe the unordered to-many relationship for which the set is the collection of related objects.
Availability
- Available in OS X v10.7 and later.
See Also
- – addObserver:forKeyPath:options:context:
Declared In
NSKeyValueObserving.h
setByAddingObject:
Returns a new set formed by adding a given object to the receiving set.
- (NSSet *)setByAddingObject:(id)anObject
Parameters
anObject
The object to add to the set.
Return Value
A new set formed by adding anObject to the receiving set.
Availability
- Available in OS X v10.5 and later.
See Also
- + set
- + setWithArray:
- + setWithObject:
- + setWithObjects:
- – setByAddingObjectsFromSet:
- – setByAddingObjectsFromArray:
Declared In
NSSet.h
setByAddingObjectsFromArray:
Returns a new set formed by adding the objects in a given array to the receiving set.
- (NSSet *)setByAddingObjectsFromArray:(NSArray *)other
Parameters
other
The array of objects to add to the set.
Return Value
A new set formed by adding the objects in other to the receiving set.
Availability
- Available in OS X v10.5 and later.
See Also
- + set
- + setWithArray:
- + setWithObject:
- + setWithObjects:
- – setByAddingObject:
- – setByAddingObjectsFromSet:
Declared In
NSSet.h
setByAddingObjectsFromSet:
Returns a new set formed by adding the objects in a given set to the receiving set.
- (NSSet *)setByAddingObjectsFromSet:(NSSet *)other
Parameters
other
The set of objects to add to the receiving set.
Return Value
A new set formed by adding the objects in other to the receiving set.
Availability
- Available in OS X v10.5 and later.
See Also
- + set
- + setWithArray:
- + setWithObject:
- + setWithObjects:
- – setByAddingObject:
- – setByAddingObjectsFromArray:
Declared In
NSSet.h
setValue:forKey:
Invokes setValue:forKey: on each of the set’s members.
- (void)setValue:(id)value forKey:(NSString *)key
Parameters
value
The value for the property identified by key.
key
The name of one of the properties of the set's members.
Availability
- Available in OS X v10.4 and later.
See Also
- – valueForKey:
Declared In
NSKeyValueCoding.h
sortedArrayUsingDescriptors:
Returns an array of the set’s content sorted as specified by a given array of sort descriptors.
- (NSArray *)sortedArrayUsingDescriptors:(NSArray *)sortDescriptors
Parameters
sortDescriptors
An array of NSSortDescriptor objects.
Return Value
An NSArray containing the set’s content sorted as specified by sortDescriptors.
Discussion
The first descriptor specifies the primary key path to be used in sorting the set’s contents. Any subsequent descriptors are used to further refine sorting of objects with duplicate values. SeeNSSortDescriptor for additional information.
Availability
- Available in OS X v10.6 and later.
Declared In
NSSortDescriptor.h
valueForKey:
Return a set containing the results of invoking valueForKey: on each of the receiving set's members.
- (id)valueForKey:(NSString *)key
Parameters
key
The name of one of the properties of the receiving set's members.
Return Value
A set containing the results of invoking valueForKey: (with the argument key) on each of the receiving set's members.
Discussion
The returned set might not have the same number of members as the receiving set. The returned set will not contain any elements corresponding to instances ofvalueForKey: returning nil (note that this is in contrast withNSArray’s implementation, which may put NSNull values in the arrays it returns).
Availability
- Available in OS X v10.4 and later.
See Also
- – setValue:forKey:
Declared In
NSKeyValueCoding.h
Next
Copyright © 2013 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2013-09-18
Provide Feedback
- Nsset
- NSSet
- NSSet
- NSSet
- NSSet
- NSSet
- NSSet
- NSSet
- NSSet
- nsset
- NSSet
- NSSet
- NSSet
- NSSet详解
- NSSet详解
- NSSet 札记
- NSSet sort
- NSSet、NSMutableSet
- 图解MYSQL_JOIN_ON_SQL_JOIN_详解_数据库sql_join语句
- 淘派电商彰显南京云锦神韵
- ios反射调用类的方法(objectiveC)
- C# WINFORM TEXTBOX水印效果
- Android 动态加载(防止逆向编译)技术
- NSSet
- pthread学习
- 使用Jsoup 抓取页面的数据
- Redis的java客户端Jedis
- jquery UI
- Spring中注解事务@Transactional说明 .
- 黑马程序员——JavaIO—概述
- 数据库同步操作
- NSMutableSet