Take away (when ordering food): is it 带走 or 打包? I was told that when you are ordering food you can say either 带走 or 打包. 

However, when you are not ordering food and you mean "take this away", then you use 拿走。 

Is there a difference in context or meaning between 带走 and 打包?
In my experience (Beijing), 带走 means take away or take out. 打包 means you want a doggy bag.
Update: As a result of further observation, I've found that both 带走 and 打包 mean take away. However, if you want a doggy bag you would probably say 打包.