Objective-c 集合对象

　　集合（NSSet）是一组单值对象的组合，集合对象的操作包括：搜索，添加，删除集合中的成员（可变集合的功能），比较两个集合，计算两个集合的交集，并集等。

　　下面来看下（NSSet）的方法：

　　

　　1）集合的构建

　　

 // 构建集合的三种方法

 #import <Foundation/Foundation.h>

 int main(int argc , const char *argv[]){
     @autoreleasepool {
         NSSet *set1 = [NSSet setWithObjects:@"zhangsan",@"lisi",@"wangwu",nil];
         for(NSString *temp1 in set1){
             NSLog(@"temp1 = %@",temp1);
         }

         NSArray *array = @[@"aa",@"bb",@"cc"];
         NSSet *set2 = [NSSet setWithArray:array];
         for(NSString *temp2 in set2)
             NSLog(@"temp2 = %@",temp2);

         NSSet *set3 = [[NSSet alloc] initWithObjects:@"aa",@"bb"@"cc",nil];
         for(NSString *temp3 in set3)
             NSLog(@"temp3 = %@",temp3);
     }
 }

　　2）集合的遍历

　　

 #import <Foundation/Foundation.h>

 @interface NSString (print)

 - (void)print;
 - (void)show:(NSString *)str;

 @end

 @implementation NSString (print)

 - (void)print{
     NSLog(@"%@",self);
 }
 - (void)show:(NSString *)str{
     NSLog(@"%@ : %@",str,self);
 }

 @end
 int main(int argc , const char *argv[]){
     @autoreleasepool {
         NSSet *set = [NSSet setWithObjects:@"zhangsan",@"lisi",@"wangwu",nil];
         for(NSString *temp in set)
             NSLog(@"temp = %@",temp);

         NSLog(@"--------------------------");
         [set enumerateObjectsUsingBlock:^(id obj, BOOL *stop) {
             NSLog(@"obj = %@",obj);
         }];

         NSLog(@"---------------------------");
         [set makeObjectsPerformSelector:@selector(print)];

         NSLog(@"----------------------------");
         [set makeObjectsPerformSelector:@selector(show:) withObject:@"this is "];

         NSLog(@"-----------------------------");
         NSEnumerator *emr = [set objectEnumerator];
         NSString *temp = nil;
         while(temp = [emr nextObject])
             NSLog(@"temp = %@",temp);
     }
     return ;
 }

3) 集合的比较

　　

 #import <Foundation/Foundation.h>

 int main(int argc , const char *argv[]){
     @autoreleasepool {
         NSSet *set = [NSSet setWithObjects:@"zhangsan",@"lisi",@"wangwu",nil];
         for(NSString *temp in set)
             NSLog(@"temp = %@",temp);

         BOOL ishas = [set containsObject:@"lisi"];
         if(ishas)
             NSLog(@"has lisi");
         else
             NSLog(@"no lisi");

         NSString *str = [set member:@"aaaa"];
         NSLog(@"str = %@",str);

         NSSet *set2 = [set setByAddingObject:@"xiaoliu"];
         NSLog(@"set2 = %@",set2);

         NSSet *set3 = [set setByAddingObjectsFromArray:@[@"aa",@"bb",@"cc"]];
         NSLog(@"set3 = %@",set3);

         NSSet *set4 = [NSSet setWithObjects:@"zhangsan",@"lisi",nil];
         BOOL issub = [set4 isSubsetOfSet:set];
         if(issub)
             NSLog(@"set4 is set sub class");
         else
             NSLog(@"set4 no set sub class");

         BOOL isinterset = [set intersectsSet:set4];
         if(isinterset)
             NSLog(@"set and set4 has intersect");
         else
             NSLog(@"set and set4 no intersect");

         BOOL isequal = [set isEqualToSet:set2];
         if(isequal)
             NSLog(@"set = set2");
         else
             NSLog(@"set != set2");

     }
     return ;
 }

　　4）可变集合(NSMutable)

　　

　　下面通过一个例子来说可变集合的用法：

　　

 #import <Foundation/Foundation.h>

 @interface NSString (print)
 -(void)print;
 -(void)show:(NSString *)str;
 @end

 @implementation NSString(print)
 -(void)print{
     NSLog(@"%@",self);
 }
 -(void)show:(NSString *)str{
     NSLog(@"%@ : %@",str,self);
 }
 @end

 int main(int argc,char **argv){
     @autoreleasepool {
         NSMutableSet *mset = [NSMutableSet setWithObjects:@"zhangsan",@"lisi",@"wangwu", nil];

         [mset addObject:@"zhaoliu"];
         NSLog(@"mset = %@",mset);

         [mset addObjectsFromArray:@[@"",@"",@""]];
         NSLog(@"mset = %@",mset);

         [mset removeObject:@""];
         NSLog(@"mset = %@",mset);

         NSSortDescriptor *sortdesr = [[NSSortDescriptor alloc] initWithKey:nil ascending:YES];
         NSArray *sortset = [mset sortedArrayUsingDescriptors:@[sortdesr]];
         NSLog(@"mset sort = %@",sortset);

         NSArray *array = [mset allObjects];
         NSLog(@"array = %@",array);
         NSSet *set2 = [NSSet setWithArray:array];
         NSLog(@"set2 = %@",set2);

         NSString *str = [mset anyObject];
         NSLog(@"str = %@",str);

         [mset setSet:set2];
         NSLog(@"mset = %@",mset);

         [mset removeAllObjects];
         NSLog(@"mset = %@",mset);
     }
 }