如何在不创建新内容的情况下更改UIPicker的内容？

I am a complete newbie in Swift, so excuse me if it may be a dumb question. I am trying to implement a way so that the content in the picker changes depending on which button is clicked. For example, let say there are two buttons "Months" and "Years". If I click Months button, I want a picker to appear with all it's content. But once I click Years button, I would like the same picker to appear with all the years instead (vice versa).I am a complete newbie in Swift, so excuse me i