What is the correct way to “clear" a std::string_view?

Question

I see this post: c++ - Why doesn't std::string_view have assign() and clear() methods? - Stack Overflow , so string_view does not contain clear function.

But in my case, I have a string_view as a class member variable, and sometimes, I would like to reset it to an empty string. Currently, I'm using this way:

sv = "";

Which looks OK, but I'd see other suggestions, thanks!

Answer 1

An empty "" string is still a string of length zero. While that will work, data() will not return a nullptr the way it would for a truly empty string_view . If you do want to reset the string_view , it would be best to assign an empty string_view to it: sv = string_view{}; .

Answer 2

If what you want is to set the size of the string_view to zero, then what you're doing is OK (at the cost of a byte somewhere in your binary).

There are alternatives in the post that you referenced:

• sv = {}
• sv = sv.substr(0, 0)

Yet another way:

• sv.remove_prefix(sv.size())