[R] transform 3 numeric vectors empty of 0/1

[Arnaud Michel]

Dear all,
Without a loop, I would like transform 3 numeric vectors empty of 0/1 of 
same length
Vec1 : transform 1 to A and 0 to ""
Vec2 : transform 1 to B and 0 to ""
Vec3 : transform 1 to C and 0 to ""
to obtain only 1 vector Vec who is the paste of the 3 vectors (Ex : ABC, 
BC, AC, AB,...)
Any idea ?
Thank you for your help

-- 
Michel ARNAUD