Q:

re-using column specifications in tabular

I have multiple tables which have a arbitrary fixed set of column specifications.
e.g 
\begin{tabular}{@{}lccp{2cm}rcp{2cm}@{}}
blah
\end{tabular}

I would like to save and reuse the arguments @{}lccp{2cm}rcp{2cm}@{} over and over again for other tables.
I tried:
\newcommand{\tabformat}{@{} etc}
and then
\begin{tabular}{\tabformat}
blah
\end{tabular}

and I also tried spraying the code with multiple \protect statements, but I couldn't get it to work.
MnWE is:
\documentclass{article}
\usepackage{booktabs,array}
\begin{document}

\newcommand{\tabformat}{llrrllrr}
\begin{tabular}{\tabformat} 
blah
\end{tabular}   
\end{document}

How do I do this?

A:

\documentclass{article}
\usepackage{booktabs,array}
\begin{document}

\newcolumntype\tabformat{llrrllrr}
\begin{tabular}{\tabformat}
blah&blb & bl\\
a& b & c
\end{tabular}
\end{document}

