NSArray,NSMutableArray,NSDictionary,NSMutableDictionary总结

    NSArray，NSDictionary只能读，不能写。NSMutableArray，NSMutableDictionary可读写

    NSMutableArray的主要方法如下：

    增加：addobject：

    删除：removeAllObjects，RemoveObjecAtIndex,RemoveObject

    修改：replaceObjectAtIndex：withObject：

    查看：ObjectAtIndex：

例子：

    NSArray *array = [[NSArray alloc]initWithObjects:@"One",@"Two",@"Three", nil];

    for (int i=0; i<[array count]; i++) {

        NSString *str = [array objectAtIndex:i];

        NSLog(@"%@ \n",str);

    }

    

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

    //zeng

    [multArray addObject:@"One"];

    [multArray addObject:@"Two"];

    [multArray addObject:@"Three"];

    [multArray addObject:@"Four"];

    [multArray addObject:@"Five"];

    //cha

    for (int i=0; i<[multArray count]; i++) {

        NSString *str = [multArray objectAtIndex:i];

        NSLog(@"%@ \n",str);

    }

    //shan

    [multArray removeObjectAtIndex:2];

    for (int i=0; i<[multArray count]; i++) {

        NSString *str = [multArray objectAtIndex:i];

        NSLog(@"%@ \n",str);

    }

    //shan

    [multArray removeObject:@"Four"];

    for (int i=0; i<[multArray count]; i++) {

        NSString *str = [multArray objectAtIndex:i];

        NSLog(@"%@ \n",str);

    }

    //shan

    NSLog(@"TEST:::::::::::::::::5");

    [multArray removeObject:@"Four111"];

    for (int i=0; i<[multArray count]; i++) {

        NSString *str = [multArray objectAtIndex:i];

        NSLog(@"%@ \n",str);

    }

    //gai

    [multArray replaceObjectAtIndex:1 withObject:@"TwoTwoTwo"];

    for (int i=0; i<[multArray count]; i++) {

        NSString *str = [multArray objectAtIndex:i];

        NSLog(@"%@ \n",str);

    }

    

    NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:0],@"Zero", array,@"array", nil];

    

    //du

    NSNumber *number = [dict objectForKey:@"Zero"];

    NSArray *myArray = [dict objectForKey:@"array"];

    //NSString *str1 = [myArray objectAtIndex:100];//err 会crash

    //err

    NSArray *errArray = [dict objectForKey:@"XXXX"];

    NSArray *errArray1 = [dict objectForKey:@"Zero"];

    

    

    NSString *string = @"1,2,3,4,5,6,";

    NSArray *strArray = [string componentsSeparatedByString:@","];

    for (int i = 0; i<[strArray count]; i++) {

        NSLog(@"%@ \n",[strArray objectAtIndex:i]);

    }

注意：

     ObjectAtIndex，如果越界，则会Crash

     ObjectForKey，如果key不存在，则只会让其为空