Hiding a column with colored cells

\documentclass{article}
\usepackage{array}
\usepackage{colortbl}
\makeatletter
\def\zz{\aftergroup\zzz}
\def\zzz\begingroup#1\endgroup
    {\global\let\CT@do@color\relax\global\let\CT@cell@color\relax}
\newcommand{\gc}{\cellcolor[gray]{.7}}
\newcolumntype{H}
   {>{\setbox0=\hbox\bgroup\bgroup}c<{\egroup\egroup\aftergroup\aftergroup\aftergroup\zz}@{}}

\newcommand{\tablebody}{%
      foo &     bar & \gc boo &     baz &     faa \\
      bar & \gc boo &     baz & \gc faa &     foo \\
  \gc boo &     baz &     faa &     foo & \gc bar \\
      baz & \gc faa &     foo & \gc bar &     boo \\
      faa &     foo & \gc bar &     boo &     baz %
}

\begin{document}

\section*{all columns visible}

\begin{tabular}{ccccc}
  \tablebody
\end{tabular}

\section*{center column hidden}

\begin{tabular}{ccHcc}
  \tablebody
\end{tabular}

\section*{middle columns hidden}

\begin{tabular}{cHcHc}
  \tablebody
\end{tabular}

\section*{outer columns hidden}

\begin{tabular}{HcccH}
  \tablebody
\end{tabular}

\end{document}

This is, I hope, an improvement over my earlier attempt. To eliminate the residual color, I had to set \tabcolsep to 0pt. I then used @{\extracolsep{1ex}} to add column gap back in. The only downside is that the extracolsep will not be colored in a cell, but that may be a workable solution.

\documentclass{article}
\usepackage{array}
\usepackage{colortbl}
\let\svtabcolsep\tabcolsep
\setlength\tabcolsep{0pt}
\newcommand{\gc}{\cellcolor[gray]{.7}}
\newcolumntype{H}{>{\setbox0=\hbox\bgroup}c<{\egroup}@{}}

\newcommand{\tablebody}{%
      foo &     bar & \gc boo &     baz &     faa \\
      bar & \gc boo &     baz & \gc faa-extra-extra long &     foo \\
  \gc boo &     baz &     faa &     foo & \gc bar \\
      baz & \gc faa &     foo & \gc bar &     boo \\
      faa &     foo-extra long & \gc bar &     boo &     baz %
}

\begin{document}

\section*{all columns visible}

\begin{tabular}{@{\extracolsep{1ex}}ccccc}
  \tablebody
\end{tabular}

\section*{center column hidden}

\begin{tabular}{@{\extracolsep{1ex}}ccHcc}
  \tablebody
\end{tabular}

\section*{middle columns hidden}

\begin{tabular}{@{\extracolsep{1ex}}cHcHc}
  \tablebody
\end{tabular}

\section*{outer columns hidden}

\begin{tabular}{@{\extracolsep{1ex}}HcccH}
  \tablebody
\end{tabular}

\end{document}