2つの配列を比較し、等しいオブジェクトを新しい配列に入れよう

Question

NSArrayを2つ比較し、等しいオブジェクトを新しい配列に挿入するにはどうすればよいですか？

Answer 1

NSArray *array1 = [[NSArray alloc] initWithObjects:@"a",@"b",@"c",nil]; 
    NSArray *array2 = [[NSArray alloc] initWithObjects:@"a",@"d",@"c",nil]; 
    NSMutableArray *ary_result = [[NSMutableArray alloc] init]; 
    for(int i = 0;i<[array1 count];i++) 
    { 
     for(int j= 0;j<[array2 count];j++) 
     { 
      if([[array1 objectAtIndex:i] isEqualToString:[array2 objectAtIndex:j]]) 
      { 
       [ary_result addObject:[array1 objectAtIndex:i]]; 
       break; 
      } 
     } 
    } 
    NSLog(@"%@",ary_result);//it will print a,c 

Answer 2

回答：

NSArray *firstArr, *secondArr; 
// init arrays here 
NSMutableArray *intersection = [NSMutableArray array]; 
for (id firstEl in firstArr) 
{ 
    for (id secondEl in secondArr) 
    { 
     if (firstEl == secondEl) [intersection addObject:secondEl]; 
    } 
} 
// intersection contains equal objects 

オブジェクトメソッドcompare:を用いて比較します。あなたが別の方法を使用したい場合は、単に同じオブジェクトにYES返すようyourComparatorとif (firstEl == secondEl)を置き換える：if ([firstEl yourComparator:secondEl])

Answer 3

//i assume u have first and second array with objects 

//NSMutableArray *first = [ [ NSMutableArray alloc]init]; 

//NSMutableArray *second = [ [ NSMutableArray alloc]init];        

NSMutableArray *third = [ [ NSMutableArray alloc]init]; 


    for (id obj in first) { 

     if ([second containsObject:obj]) { 


      [third addObject:obj]; 

     } 


    } 


NSLog(@"third is : %@ \n\n",third); 


more over if u have strings in both array then look at this answer of mine 

Finding Intersection of NSMutableArrays