iOS 遍历数组，提取相同元素存入另外一个数组

代码如下：

NSArray *array1 = @[@"2016-10-01",@"2016-10-02",@"2016-10-03",
                        
                        @"2016-10-01",@"2016-10-02",@"2016-10-03",
                        
                        @"2016-10-01",@"2016-10-02",@"2016-10-03",
                        
                        @"2016-10-01",@"2016-10-02",@"2016-10-03",
                        
                        @"2016-10-01",@"2016-10-02",@"2016-10-03",
                        
                        @"2016-10-01",@"2016-10-02",@"2016-10-03",
                        
                        @"2016-10-04",@"2016-10-06",@"2016-10-08",
                        
                        @"2016-10-05",@"2016-10-07",@"2016-10-09"];
    NSMutableArray *array = [NSMutableArray arrayWithArray:array1];
    
    NSMutableArray *dateMutablearray = [@[] mutableCopy];
    for (int i = 0; i < array.count; i ++) {
        
        NSString *string = array[i];
        
        NSMutableArray *tempArray = [@[] mutableCopy];
        
        [tempArray addObject:string];
        
        for (int j = i+1; j < array.count; j ++) {
            
            NSString *jstring = array[j];
            
            if([string isEqualToString:jstring]){
                
                [tempArray addObject:jstring];
                
                [array removeObjectAtIndex:j];
                j -= 1;
                
            }
            
        }
        
        [dateMutablearray addObject:tempArray];
        
    }
    
    NSLog(@"dateMutable:%@",dateMutablearray);

输出结果是：