Re: [Boost-users] [Boost.Assign] list_of::range without an initial (single) element?

Michael McNeil Forbes wrote:

What is the recommended way of initializing an array from a concatenation of other arrays?

list_of::range looks right and I would like to use something like:

array a = { 1, 2 }; array b = { 3, 4 }; array c = list_of<int>().range(a).range(b);

However, list_of<int>() inserts a default value (so that list_of<int>().range(a).range(b) == {0,1,2,3,4}). There are several workarounds, e.g.

array c = list_of<int>(a[0]) .range(a.begin()+1, a.end()) .range(b); array c = boost::assign_detail::generic_list<int>() .range(a) .range(b);

The first is ugly; the second seems an abuse of assign_detail (and fails for static_generic_list).

I am sure I am missing a simple solution, but can't seem to find it.

Thanks, Michael.

The proposed extension of Boost.Assign offers an alternative approach to this problem: boost::array a = { 1, 2 }; boost::array b = { 3, 4 }; boost::array c = a && b; I have reproduced this example at the bottom of this file: http://svn.boost.org/svn/boost/sandbox/statistics/support/libs/assign/exampl.... Instructions are here: http://svn.boost.org/svn/boost/sandbox/statistics/support/libs/assign/doc/pa...