adding elements of a vector to an unordered set

Question

Is there an easy way to add all the elements of a vector to an unordered_set? They are of the same type. Right now, I am using a for loop and was wondering if there is a better way to do it

Solution 1

If you're constructing the unordered_set then:

std::vector<int> v;
std::unordered_set<int> s(v.begin(), v.end());

Solution 2

Forgive me if my syntax has any minor bugs, but you can try the std::copy function, its meant for this purpose.

std::vector<int> v;
std::unordered_set<int> s;
std::copy(v.begin(),v.end(),std::inserter(s,s.end()));

Comments

[James McNellis]

std::inserter is required to insert into an associative container.

[Karthik T]

yup, i knew i missed something, fixed.

[Johannes Schaub - litb]

does s.end() remain valid even if the container rehashes?

[James Harper]

if v is empty then an 0 will be added to s!