Best way to extract a subvector from a vector?

c++ stl vector range
An̲̳̳drew picture An̲̳̳drew · Jan 7, 2009 · Viewed 348.4k times · Source

Suppose I have a std::vector (let's call it myVec) of size N. What's the simplest way to construct a new vector consisting of a copy of elements X through Y, where 0 <= X <= Y <= N-1? For example, myVec [100000] through myVec [100999] in a vector of size 150000.

If this cannot be done efficiently with a vector, is there another STL datatype that I should use instead?

Answer

Greg Rogers picture Greg Rogers · Jan 7, 2009 
vector<T>::const_iterator first = myVec.begin() + 100000;
vector<T>::const_iterator last = myVec.begin() + 101000;
vector<T> newVec(first, last);

It's an O(N) operation to construct the new vector, but there isn't really a better way.

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