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<a name="Creating-Cell-Arrays"></a>
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<p>
Next: <a href="Indexing-Cell-Arrays.html#Indexing-Cell-Arrays" accesskey="n" rel="next">Indexing Cell Arrays</a>, Previous: <a href="Basic-Usage-of-Cell-Arrays.html#Basic-Usage-of-Cell-Arrays" accesskey="p" rel="prev">Basic Usage of Cell Arrays</a>, Up: <a href="Cell-Arrays.html#Cell-Arrays" accesskey="u" rel="up">Cell Arrays</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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<hr>
<a name="Creating-Cell-Arrays-1"></a>
<h4 class="subsection">6.2.2 Creating Cell Arrays</h4>

<p>The introductory example (see <a href="Basic-Usage-of-Cell-Arrays.html#Basic-Usage-of-Cell-Arrays">Basic Usage of Cell Arrays</a>) showed
how to create a cell array containing currently available variables.
In many situations, however, it is useful to create a cell array and
then fill it with data.
</p>
<p>The <code>cell</code> function returns a cell array of a given size, containing
empty matrices.  This function is similar to the <code>zeros</code>
function for creating new numerical arrays.  The following example creates
a 2-by-2 cell array containing empty matrices
</p>
<div class="example">
<pre class="example">c = cell (2,2)
     &rArr; c =

         {
           [1,1] = [](0x0)
           [2,1] = [](0x0)
           [1,2] = [](0x0)
           [2,2] = [](0x0)
         }
</pre></div>

<p>Just like numerical arrays, cell arrays can be multi-dimensional.  The
<code>cell</code> function accepts any number of positive integers to describe
the size of the returned cell array.  It is also possible to set the size
of the cell array through a vector of positive integers.  In the
following example two cell arrays of equal size are created, and the size
of the first one is displayed
</p>
<div class="example">
<pre class="example">c1 = cell (3, 4, 5);
c2 = cell ( [3, 4, 5] );
size (c1)
     &rArr; ans =
         3   4   5
</pre></div>

<p>As can be seen, the <a href="Object-Sizes.html#XREFsize">size</a> function also works
for cell arrays.  As do other functions describing the size of an
object, such as <a href="Object-Sizes.html#XREFlength">length</a>, <a href="Object-Sizes.html#XREFnumel">numel</a>,
<a href="Object-Sizes.html#XREFrows">rows</a>, and <a href="Object-Sizes.html#XREFcolumns">columns</a>.
</p>
<a name="XREFcell"></a><dl>
<dt><a name="index-cell"></a>: <em></em> <strong>cell</strong> <em>(<var>n</var>)</em></dt>
<dt><a name="index-cell-1"></a>: <em></em> <strong>cell</strong> <em>(<var>m</var>, <var>n</var>)</em></dt>
<dt><a name="index-cell-2"></a>: <em></em> <strong>cell</strong> <em>(<var>m</var>, <var>n</var>, <var>k</var>, &hellip;)</em></dt>
<dt><a name="index-cell-3"></a>: <em></em> <strong>cell</strong> <em>([<var>m</var> <var>n</var> &hellip;])</em></dt>
<dd><p>Create a new cell array object.
</p>
<p>If invoked with a single scalar integer argument, return a square
NxN cell array.  If invoked with two or more scalar integer
arguments, or a vector of integer values, return an array with the given
dimensions.
</p>
<p><strong>See also:</strong> <a href="Cell-Arrays-of-Strings.html#XREFcellstr">cellstr</a>, <a href="#XREFmat2cell">mat2cell</a>, <a href="#XREFnum2cell">num2cell</a>, <a href="Processing-Data-in-Structures.html#XREFstruct2cell">struct2cell</a>.
</p></dd></dl>


<p>As an alternative to creating empty cell arrays, and then filling them, it
is possible to convert numerical arrays into cell arrays using the
<code>num2cell</code>, <code>mat2cell</code> and <code>cellslices</code> functions.
</p>
<a name="XREFnum2cell"></a><dl>
<dt><a name="index-num2cell"></a>: <em><var>C</var> =</em> <strong>num2cell</strong> <em>(<var>A</var>)</em></dt>
<dt><a name="index-num2cell-1"></a>: <em><var>C</var> =</em> <strong>num2cell</strong> <em>(<var>A</var>, <var>dim</var>)</em></dt>
<dd><p>Convert the numeric matrix <var>A</var> to a cell array.
</p>
<p>If <var>dim</var> is defined, the value <var>C</var> is of dimension 1 in this
dimension and the elements of <var>A</var> are placed into <var>C</var> in slices.
For example:
</p>
<div class="example">
<pre class="example">num2cell ([1,2;3,4])
   &rArr;
      {
        [1,1] =  1
        [2,1] =  3
        [1,2] =  2
        [2,2] =  4
      }
num2cell ([1,2;3,4],1)
   &rArr;
      {
        [1,1] =
           1
           3
        [1,2] =
           2
           4
      }
</pre></div>


<p><strong>See also:</strong> <a href="#XREFmat2cell">mat2cell</a>.
</p></dd></dl>


<a name="XREFmat2cell"></a><dl>
<dt><a name="index-mat2cell"></a>: <em><var>C</var> =</em> <strong>mat2cell</strong> <em>(<var>A</var>, <var>m</var>, <var>n</var>)</em></dt>
<dt><a name="index-mat2cell-1"></a>: <em><var>C</var> =</em> <strong>mat2cell</strong> <em>(<var>A</var>, <var>d1</var>, <var>d2</var>, &hellip;)</em></dt>
<dt><a name="index-mat2cell-2"></a>: <em><var>C</var> =</em> <strong>mat2cell</strong> <em>(<var>A</var>, <var>r</var>)</em></dt>
<dd><p>Convert the matrix <var>A</var> to a cell array.
</p>
<p>If <var>A</var> is 2-D, then it is required that
<code>sum (<var>m</var>) == size (<var>A</var>, 1)</code> and
<code>sum (<var>n</var>) == size (<var>A</var>, 2)</code>.  Similarly, if <var>A</var> is
multi-dimensional and the number of dimensional arguments is equal to the
dimensions of <var>A</var>, then it is required that
<code>sum (<var>di</var>) == size (<var>A</var>, i)</code>.
</p>
<p>Given a single dimensional argument <var>r</var>, the other dimensional
arguments are assumed to equal <code>size (<var>A</var>,<var>i</var>)</code>.
</p>
<p>An example of the use of mat2cell is
</p>
<div class="example">
<pre class="example">mat2cell (reshape (1:16,4,4), [3,1], [3,1])
&rArr;
{
   [1,1] =

      1   5   9
      2   6  10
      3   7  11

   [2,1] =

      4   8  12

   [1,2] =

     13
     14
     15

   [2,2] = 16
}
</pre></div>

<p><strong>See also:</strong> <a href="#XREFnum2cell">num2cell</a>, <a href="Processing-Data-in-Cell-Arrays.html#XREFcell2mat">cell2mat</a>.
</p></dd></dl>


<a name="XREFcellslices"></a><dl>
<dt><a name="index-cellslices"></a>: <em><var>sl</var> =</em> <strong>cellslices</strong> <em>(<var>x</var>, <var>lb</var>, <var>ub</var>, <var>dim</var>)</em></dt>
<dd><p>Given an array <var>x</var>, this function produces a cell array of slices from
the array determined by the index vectors <var>lb</var>, <var>ub</var>, for lower and
upper bounds, respectively.
</p>
<p>In other words, it is equivalent to the following code:
</p>
<div class="example">
<pre class="example">n = length (lb);
sl = cell (1, n);
for i = 1:length (lb)
  sl{i} = x(:,&hellip;,lb(i):ub(i),&hellip;,:);
endfor
</pre></div>

<p>The position of the index is determined by <var>dim</var>.  If not specified,
slicing is done along the first non-singleton dimension.
</p>
<p><strong>See also:</strong> <a href="Processing-Data-in-Cell-Arrays.html#XREFcell2mat">cell2mat</a>, <a href="Indexing-Cell-Arrays.html#XREFcellindexmat">cellindexmat</a>, <a href="Function-Application.html#XREFcellfun">cellfun</a>.
</p></dd></dl>


<hr>
<div class="header">
<p>
Next: <a href="Indexing-Cell-Arrays.html#Indexing-Cell-Arrays" accesskey="n" rel="next">Indexing Cell Arrays</a>, Previous: <a href="Basic-Usage-of-Cell-Arrays.html#Basic-Usage-of-Cell-Arrays" accesskey="p" rel="prev">Basic Usage of Cell Arrays</a>, Up: <a href="Cell-Arrays.html#Cell-Arrays" accesskey="u" rel="up">Cell Arrays</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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