功能

迭代器具有遍歷陣列的功能
(迭代器可以有效的改變多次移除崩潰的問題)

NSArray *arr [email protected][@"1", @"2", @"3", @"4"];
    NSEnumerator *enumerator =[arr objectEnumerator];
    NSString *str;
    while (str = [enumerator nextObject]) {
        NSLog(@"%@", str);
    }
    結果:
    2015-07-23 20:48:14.375 OC07_NSDate[536
 
:20989] 1
    2015-07-23 20:48:14.375 OC07_NSDate[536:20989] 2
    2015-07-23 20:48:14.375 OC07_NSDate[536:20989] 3
    2015-07-23 20:48:14.375 OC07_NSDate[536:20989] 4

迭代器遍歷字典

列印字典中的 Value

NSDictionary *dic=[NSDictionary dictionaryWithObjectsAndKeys:@"1",@"2",@"3",@"4",@"5",@"6", nil];
     NSEnumerator *enumerator =[dic objectEnumerator];
    NSString
 
 *str =nil;
    while (str=[enumerator nextObject]) {
        NSLog(@"%@",str);
    }
    結果:
    2015-07-23 20:51:12.598 OC07_NSDate[545:22386] 1
    2015-07-23 20:51:12.599 OC07_NSDate[545:22386] 3
    2015-07-23 20:51:12.599 OC07_NSDate[545:22386] 5

把基本資料型別轉化成物件型別

NSInteger a =10;
    //  integer -> NSNumber
 

    NSNumber *number =[[NSNumber alloc] initWithInteger:a];
    NSLog(@"%@",number);
    // NSNumber ->integer
    NSInteger *b =[number integerValue ];