Aligning a Multi-line Expression in Table

Question

I am so close to having this aligned properly, but the right-most cell is flush against the top rule whereas the left-most and center cells have a small amount of vertical space. I am trying to make the alignment uniform (either remove vertical space, or have it consistent across the row).

I've used \parbox{} to allow the multiline expression to be contained within, and horizontally aligned within, the table.

\begin{table}[h]
\caption{Title of Table.}
\begin{tabularx}{\linewidth}{p{1.4cm} p{6.9cm} p{6.8cm}} 
\toprule
Head1 & Head2 & Head3 \\
\midrule
text   & text text text text &  \parbox{6.8cm}{$BZ, CY, CX, BZ, BX, AY, AZ, \\ CY, CZ, \ldots$ } \\
\bottomrule
\end{tabularx}
\end{table}

Also, in case this is important, I have the following in my preamble for APA-formatted tables.

\DeclareCaptionLabelSeparator*{spaced}{\\[2ex]}
\captionsetup[table]{textfont=it,format=plain,justification=justified,
  singlelinecheck=false,labelsep=spaced,skip=0pt}
\captionsetup[figure]{labelsep=period,labelfont=it,justification=justified,
  singlelinecheck=false,font=doublespacing}

Answer 1

It's not very clear what you want to achieve, you should provide a complete minimal example.

Anyway, with tabularray:

\documentclass{article}
\usepackage{tabularray}
\UseTblrLibrary{booktabs} 
\usepackage{caption}
\DeclareCaptionLabelSeparator*{spaced}{\\[2ex]}
\captionsetup[table]{textfont=it,format=plain,justification=justified,
    singlelinecheck=false,labelsep=spaced,skip=0pt}
\captionsetup[figure]{labelsep=period,labelfont=it,justification=justified,
    singlelinecheck=false,font=doublespacing}

\begin{document}
    \begin{table}[h]
        \caption{Title of Table.}
        \begin{tblr}{colspec={Q[1.4cm]Q[6.9cm]X[mode=math]}} 
            \toprule
            Head1 & Head2 & Head3 \\
            \midrule
            text   & text text text text & {BZ, CY, CX, \\ BZ, BX, AY,\\ AZ, CY, CZ, \ldots} \\
            \bottomrule
        \end{tblr}
    \end{table}
\end{document}

Answer 2

Note that a tabularx environment requires the use of an X-column in order to work properly. Without one, you might as well just use a regular tabular. Secondly, and what you're looking to change, a list of inline math elements are not breakable around ,. You'll have to change how that is managed by using content from (say) “Allowing line break at ',' in inline math mode” breaks citations:

\documentclass{article}

\usepackage{tabularx,booktabs}

% https://tex.stackexchange.com/a/19100/5764
\mathchardef\breakingcomma\mathcode`\,
{\catcode`,=\active
  \gdef,{\breakingcomma\discretionary{}{}{}}
}
\newcommand{\mathlist}[1]{\mathcode`\,=\string"8000 #1}

\begin{document}

\begin{table}
  \caption{Table caption}
  \begin{tabularx}{\linewidth}{ p{14mm} p{69mm} X } 
    \toprule
    Head1 & Head2 & Head3 \\
    \midrule
    text & text text text text & $\mathlist{BZ, CY, CX, BZ, BX, AY, AZ, CY, CZ, \ldots}$ \\
    \bottomrule
  \end{tabularx}
\end{table}

\end{document}

Answer 3

https://tex.stackexchange.com/a/467445/197451

\documentclass{article}
\usepackage{tabularx}
\usepackage{booktabs}
\usepackage{multirow}

\newcolumntype{C}{>{\centering\arraybackslash}X}
\renewcommand\tabularxcolumn[1]{m{#1}}

\begin{document}
    \begin{table}[h]
        \caption{Title of Table.}
\setlength{\extrarowheight}{2pt}
        \begin{tabularx}{\linewidth}{ccC} 
            \toprule
            Head1 & Head2 & Head3 \\
            \midrule
            text   & text text text text &{{\parbox{3cm}{$BZ, CY, CX, BZ, BX,\\ AY, 
            AZ, CY, CZ, \ldots$ }}} \\
            \bottomrule
        \end{tabularx}
    \end{table}
    \begin{table}[h]
                \caption{Title of Table.}
        \begin{tabularx}{\textwidth}{ccC} 
            \toprule
            Head1 & Head2 & Head3 \\
            \midrule
            text   & text text text text &  {{$BZ, CY, CX, BZ, BX, AY, AZ, CY, CZ, 
            \ldots$ }} \\
            \bottomrule
        \end{tabularx}
    \end{table}
\end{document} 

Answer 4

The baseline of a \parbox with multiple lines of text in it is the baseline of its bottommost row, giving the whole box excessive height above the baseline. Such a box is not aligned at the baseline but at the top, making it appear flush against the rule above.

The solution is to include a "strut" in its first line of text so that the (imaginary) baseline of its topmost row aligns with the baselines in the other columns. Plain TeX offers the macros \strut and \mathstrut for this.

text & \strut text text text text &
$\mathlist{\mathstrut BZ, CY, CX, BZ, BX, AY, AZ, CY, CZ, \ldots}$ \\

See also Identical spacing of inference lines with Bussproofs.