For the only situation you gave, this code will do exactly what you asked.
s = '123456781234567812345678123456781234567812345678'
columnVector1 = s(1:8)
columnVector2 = s(9:16)
columnVector3 = s(17:24)
columnVector4 = s(25:32)
columnVector5 = s(33:40)
columnVector6 = s(41:48)
If you need something different, like a 2D array, a cell array, different lengths of input strings, etc. then you should say so - completely and explicitly specify all input and output conditions and requirements. http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer
