\section{ISEMPTY Test For Variable Empty}

\subsection{Usage}

The \verb|isempty| function returns a boolean that indicates
if the argument variable is empty or not.  The general
syntax for its use is
\begin{verbatim}
  y = isempty(x).
\end{verbatim}
\subsection{Examples}

Here are some examples of the \verb|isempty| function
\begin{verbatim}
--> a = []

a = 
  []
--> isempty(a)

ans = 

 1 

--> b = 1:3

b = 

 1 2 3 

--> isempty(b)

ans = 

 0 


\end{verbatim}
Note that if the variable is not defined, \verb|isempty| 
does not return true.
\begin{verbatim}
--> clear x
--> isempty(x)
Error: Undefined function or variable x

\end{verbatim}
