[boost] [off-topic] why do we not have std::copy_if?

I've recently wondered why std::copy doesn't have an analogous std::copy_if: template<class InIt, class OutIt, class Pr> OutIt *copy_if*(InIt first, InIt last, OutIt dest, Pr pred); that would copy elements to dest where the predicate returns true. Not unlike "grep" in Perl and "filter" in Python. The same goal can be achieved with std::remove_copy_if and the use of a sense-reversed predicate, but this leads to confusing code IMHO. Why wouldn't this be part of the Standard Library, or am I missing something ridiculously obvious? -- Caleb Epstein caleb dot epstein at gmail dot com