Q:

How to write the table width in the log file?

How do I write the table width in the log file? Say, for instance, that I have 2 tables -- when I compile the tex file, I want to write the width/breadth in the log file. Is that possible through a macro or definition, because I need to use this in my own template, rather than in a file 
\documentclass[twocolumn]{article}
\usepackage{showframe}

\begin{document}

\begin{table}[ht]
\caption{Nonlinear Model Results}
\begin{tabular}{c c c c}
\hline
Case & Method
\#1 & Method
\#2 & Method
\#3\\
\hline
1 & 50 & Sample Piece & 970\\
2 & 47 & Sample Piece & 230\\
\hline
\end{tabular}
\end{table}

\begin{table}[ht]
\caption{Nonlinear Model Results}
\begin{tabular}{c c c c}
\hline
Case & Method
\#1 & Method
\#2 & Method
\#3\\
\hline
1 & 50 & Sample Piecedgjgh aweg & 970\\
2 & 47 & Sample Piece & 230\\
\hline
\end{tabular}
\end{table}

\end{document}

A:

This cannot measure the caption width...only the tabular width.  It works by placing the tabular in a temporary box, and using \typeout to print the width into the log file.
EDITED to place this in its own environment, mtabular (measure tabular).  Additionally, mtabular now has an optional argument, to use as the ID, if the default use of \thetable is not appropriate (depending on usage).
\documentclass[twocolumn]{article}
\usepackage{showframe,environ}
\newenvironment{mtabular}[2][\thetable]{%
  \gdef\savemtabopt{#1}%
  \setbox0=\hbox\bgroup\begin{tabular}{#2}}{\end{tabular}\egroup\copy0
  \typeout{Table \savemtabopt. width is \the\wd0.}%
}
\begin{document}

\begin{table}[ht]
\caption{Nonlinear Model Results}
\begin{mtabular}{c c c c}
\hline
Case & Method
\#1 & Method
\#2 & Method
\#3\\
\hline
1 & 50 & Sample Piece & 970\\
2 & 47 & Sample Piece & 230\\
\hline
\end{mtabular}%
\end{table}

\begin{table}[ht]
\caption{Nonlinear Model Results}
\begin{mtabular}{c c c c}
\hline
Case & Method
\#1 & Method
\#2 & Method
\#3\\
\hline
1 & 50 & Sample Piecedgjgh aweg & 970\\
2 & 47 & Sample Piece & 230\\
\hline
\end{mtabular}
\end{table}

\end{document}

