在Cocoa Foundation中的NSSet和NSMutableSet ，和NSArray功能性质一样，用于存储对象属于集合。但是NSSet和NSMutableSet是无序的, 保证数据的唯一性，当插入相同的数据时，不会有任何效果。

NSSet 初始化及常用操作

#import "AppDelegate.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

• (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

  NSSet *students = [NSSet setWithObjects:@"小明", @"小辉", @"大雄", nil];
  NSSet *teachers = [[NSSet alloc] initWithObjects:@"校长", @"副校长", @"政教主任", nil];
  NSArray *array = [NSArray arrayWithObjects:@"小明", @"小辉", @"大雄",@"小李", nil];
  NSSet *students_2 = [NSSet setWithArray:array];

  NSLog(@"students :%@", students);
  NSLog(@"teachers :%@", teachers);
  NSLog(@"students_2 :%@", students_2);

  //获取集合students包含对象的个数
  NSLog(@"students count :%lu", (unsigned long)students.count);

  //以数组的形式获取集合teachers中的所有对象
  NSArray *allTeacher = [teachers allObjects];
  NSLog(@"allObj :%@", allTeacher);

  //获取teachers中任意一对象
  NSLog(@"anyObj :%@", [teachers anyObject]);

  //teachers是否包含某个对象
  if ([teachers containsObject:@"副校长"]) {
  NSLog(@"teachers中有副校长");
  }

  //是否包含指定set中的对象
  if ([students_2 intersectsSet:students]) {
  NSLog(@"intersects");
  }

  //是否完全匹配
  if ([students_2 isEqualToSet:students]) {
  NSLog(@"完全匹配");
  }else{
  NSLog(@"完全匹配？ NO。。。。。。。");
  }

  //是否是子集合
  if ([students isSubsetOfSet:students_2]) {
  NSLog(@"students isSubsetOf students_2");
  }

  //迭代器遍历
  NSEnumerator *enumerator = [teachers objectEnumerator];
  NSObject *teacher = [enumerator nextObject];
  while (teacher != nil) {
  NSLog(@"teachers中的数据: %@",teacher);
  teacher = [enumerator nextObject];
  }

  //快速枚举遍历
  for (NSObject *teacher in teachers) {
  NSLog(@"teachers中的数据: %@",teacher);
  }

  return YES;
  }

@end

NSMutableSet 初始化及常用操作

#import "AppDelegate.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

• (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

  NSMutableSet *mutableStudent = [NSMutableSet setWithObjects:@"F1", @"F2", @"F3", nil];
  NSMutableSet *mutableTeacher = [NSMutableSet setWithObjects:@"B1", @"B2", @"B3", nil];
  NSMutableSet *mutableStudent2 = [NSMutableSet setWithObjects:@"F1", @"F2", @"F3",@"F4", nil];

  //集合元素相减
  [mutableStudent2 minusSet:mutableStudent];
  NSLog(@"mutableStudent2 minus mutableStudent:%@", mutableStudent2);

  //mutableStudent2只留下相等元素
  [mutableStudent intersectSet:mutableStudent2];
  NSLog(@"intersect :%@", mutableStudent2);

  //mutableStudent合并集合
  [mutableStudent unionSet:mutableStudent2];
  NSLog(@"union :%@", mutableStudent);

  //mutableTeacher删除指定元素
  [mutableTeacher removeObject:@"好色仙人"];
  NSLog(@"removeObj :%@", mutableTeacher);

  //mutableTeacher删除所有数据
  [mutableTeacher removeAllObjects];
  NSLog(@"removeAll :%@", mutableTeacher);

  return YES;
  }

@end

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转载自【宝宝巴士SuperDo团队】 原文链接: http://www.cnblogs.com/superdo/p/4623082.html