How to do a table with fixed columns and cells spanning multiple columns?

Question

I would like to do a table like this:

I have found how to fix the column widths in: How to create fixed width table columns with text raggedright/centered/raggedleft?, How to create a table with fixed column widths and Center a fixed width text within a multicolumn .

However, when I try to merge multiple cells together with multicolumn, the column width fails:

\documentclass[10pt]{article}
\usepackage{booktabs}
\usepackage{tabularx}

\begin{document}
\begin{table}[!ht]
  \centering
  \begin{tabularx}{\linewidth}{l|X|X|X|X}
    \toprule
    Activity & \multicolumn{2}{|c|}{1st year} & \multicolumn{2}{c}{2nd year} \\
     & 1st semester & 2nd semester & 1st semester & 2nd semester  \\
    \midrule
    I. &  Perform some experiment, do some calculations, write a report and present the results in a conference.
 & & \\
  II. &  \multicolumn{3}{|c|}{Perform some experiment, do some calculations, write a report and present the results in a conference.}
  & \\
  III. &  & \multicolumn{3}{|c|}{Perform some experiment, do some calculations, write a report and present the results in a conference.} \\
    \bottomrule
  \end{tabularx}
\end{table}
\end{document}

How can I manage to do a table with fixed columns and cells spanning multiple columns?

Answer 1

With the help of \newcolumntype{L}{>{\raggedright\arraybackslash}X} in defined a new column type L. This column type is based on the X type, but its contents are left aligned instead of justified. (See also: How to create fixed width table columns with text raggedright/centered/raggedleft?)

In order to get the correct width for the \multicolumn cells, I used >{\hsize=\dimexpr3\hsize+4\tabcolsep+2\arrayrulewidth}L. Since the \multicolumn cell spans 3 L (or X) columns, we can start with >{\hsize=3\hsize}L (See also: Table layout with tabularx (column widths: 50%|25%|25%)). To this, we then add 4\tabcolsep (\tabcolsep is the small amount of horizontal white space that is added to either side of the text inside of a table cell) as well as 2\arrayrulewidth(\arrayrulewidthis the width of the vertical lines in the table.)

\documentclass{article}
\usepackage{tabularx}
\newcolumntype{L}{>{\raggedright\arraybackslash}X}
\begin{document}
\begin{table}
  \begin{tabularx}{\linewidth}{|l|L|L|L|L|}
    \hline
    Activity & \multicolumn{2}{c|}{1st year} & \multicolumn{2}{c|}{2nd year} \\ \cline{2-5}
     & 1st semester & 2nd semester & 1st semester & 2nd semester  \\
    \hline
    I. &  Perform some experiment, do some calculations, write a report and present the results in a conference.
 & & &\\ \hline
  II. &  \multicolumn{3}{>{\hsize=\dimexpr3\hsize+4\tabcolsep+2\arrayrulewidth}L|}{Perform some experiment, do some calculations, write a report and present the results in a conference.}
  & \\ \hline
  III. &  & \multicolumn{3}{>{\hsize=\dimexpr3\hsize+4\tabcolsep+2\arrayrulewidth}L|}{Perform some experiment, do some calculations, write a report and present the results in a conference.} \\
    \hline
  \end{tabularx}
\end{table}
\end{document}

---

Here is an entirely different approach based on the pgfgantt package:

\documentclass{article}
\usepackage{pgfgantt}


\begin{document}

\noindent
     \begin{ganttchart}[
     y unit title=0.5cm,
     y unit chart=1.25cm,
     x unit =1.75cm,
     vgrid,hgrid,
     title height=1,
     title label font=\footnotesize,
     bar height=0.5,
     group right shift=0,
     group top shift=0.7,
     bar label node/.style={text width=4.75cm,
                            align=right,
                            anchor=east,
                            font=\footnotesize\raggedleft}
    ]{1}{4}

  \gantttitle{1st year}{2}
  \gantttitle{2nd year}{2}         \\
  \gantttitle{1st semester}{1}
  \gantttitle{2st semester}{1}
  \gantttitle{1st semester}{1}
  \gantttitle{2st semester}{1}\\
  \ganttbar{Perform some experiment, do some calculations, write a report and present the results in a conference.}{1}{1}\\
  \ganttbar{Perform some experiment, do some calculations, write a report and present the results in a conference.}{1}{3}\\
    \ganttbar{Perform some experiment, do some calculations, write a report and present the results in a conference.}{2}{4}
\end{ganttchart}

\end{document}