OC基础语法

//        数组（NSArray/NSMutableArray)

//        不可变数组

NSArray *array1 = @[@"a",@"b",@"c",@"d"];

//创建

NSLog(@"array1 = %@",array1);

//        数组元素个数.count

NSLog(@"count = %ld",array1.count);

//        通过下标访问数组里面的元素

NSString *str = array1[0];

NSLog(@"str = %@",str);

//        可变数组NSMutableArray

NSMutableArray *mutableArray = [NSMutableArray arrayWithObjects:@"1",@"2",@"3",@"4", nil];

NSLog(@"mutableArray = %@",mutableArray);

//        元素个数：count

NSLog(@"count = %ld",mutableArray.count);

//        添加个数

[mutableArray addObject:@"5"];

NSLog(@"已添加----%@",mutableArray);

//        移除元素

[mutableArray removeObject:@"3"];

NSLog(@"已移除----%@",mutableArray);

//      字典(存放多个键值对(key-value)的一种数据类型）

//        (NSDictionary,NAMutableDictionary)

//        不可变字典NSDictionary

NSDictionary *dict = @{@"key1":@"value1",@"key2":@"value2",@"key3":@"value3"};

NSLog(@"dict = %@",dict);

NSString *string = [dict objectForKey:@"key1"];

NSLog(@"string = %@",string);

//        所有的key值，所有的value值

NSLog(@"allkeys = %@,@allvalues = %@",dict.allKeys,dict.allValues);

}

return 0;

}