TMTOWTDI: There's More Than One Way To Do It.

Therefore... what really matters? Only this ... that whatever code you write, you make your intentions perfectly clear.

Don't be unnecessarily tripped-up by thoughts of “efficiency.” Probably, no matter how you decide to do it, that won't be an issue. Just choose a strategy that obviously works, and add a short comment alerting the Next Gentle Reader of what you've done. (Even if that “Next Gentle Reader” is yourself.)