Quite a few languages allow strings to be put in either single (
') or double (
But if neither of those apply to your specific case, is there any compelling argument to prefer one type of quotes over another?…
Replying with “Who cares?” seems like a sane thing to do and until recently, I would have concurred. Indeed, it looks like a token example of something totally irrelevant. That’s why I was rather surprised to discover that there might be deep logic behind such choice.
And it’s pretty simple, really – almost obvious in hindsight. Use double quotes for strings which are to be eventually seen by user. Not necessarily the end-user, mind you; an admin or coder looking at logs is equally valid recipient. Similarly, reserve single quotes (apostrophes) for texts used internally: identifiers, enum-like values, keys within hashmaps, XML/JSON attributes, and the like.
It might still seem like somewhat superficial distinction – and blurry at times. But I think that ultimately, it pays off to focus a little on details such as these. As a benefit, we may develop a subtle sense of structure, allowing to see into underlying semantics that much quicker.