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<h3 class="section">16.3 Applying a Function to an Array</h3>
<!-- ./general/arrayfun.m -->
<p><a name="doc_002darrayfun"></a>
<div class="defun">
— Function File: <b>arrayfun</b> (<var>func, a</var>)<var><a name="index-arrayfun-1306"></a></var><br>
— Function File: <var>x</var> = <b>arrayfun</b> (<var>func, a</var>)<var><a name="index-arrayfun-1307"></a></var><br>
— Function File: <var>x</var> = <b>arrayfun</b> (<var>func, a, b, <small class="dots">...</small></var>)<var><a name="index-arrayfun-1308"></a></var><br>
— Function File: [<var>x</var>, <var>y</var>, <small class="dots">...</small>] = <b>arrayfun</b> (<var>func, a, <small class="dots">...</small></var>)<var><a name="index-arrayfun-1309"></a></var><br>
— Function File: <b>arrayfun</b> (<var><small class="dots">...</small>, "UniformOutput", val</var>)<var><a name="index-arrayfun-1310"></a></var><br>
— Function File: <b>arrayfun</b> (<var><small class="dots">...</small>, "ErrorHandler", errfunc</var>)<var><a name="index-arrayfun-1311"></a></var><br>
<blockquote>
<p>Execute a function on each element of an array. This is useful for
functions that do not accept array arguments. If the function does
accept array arguments it is better to call the function directly.
<p>The first input argument <var>func</var> can be a string, a function
handle, an inline function or an anonymous function. The input
argument <var>a</var> can be a logic array, a numeric array, a string
array, a structure array or a cell array. By a call of the function
<samp><span class="command">arrayfun</span></samp> all elements of <var>a</var> are passed on to the named
function <var>func</var> individually.
<p>The named function can also take more than two input arguments, with
the input arguments given as third input argument <var>b</var>, fourth
input argument <var>c</var>, <small class="dots">...</small> If given more than one array input
argument then all input arguments must have the same sizes, for
example
<pre class="example"> arrayfun (@atan2, [1, 0], [0, 1])
ans = [1.5708 0.0000]
</pre>
<p>If the parameter <var>val</var> after a further string input argument
"UniformOutput" is set <code>true</code> (the default), then the named
function <var>func</var> must return a single element which then will be
concatenated into the return value and is of type matrix. Otherwise,
if that parameter is set to <code>false</code>, then the outputs are
concatenated in a cell array. For example
<pre class="example"> arrayfun (@(x,y) x:y, "abc", "def", "UniformOutput", false)
ans =
{
[1,1] = abcd
[1,2] = bcde
[1,3] = cdef
}
</pre>
<p>If more than one output arguments are given then the named function
must return the number of return values that also are expected, for
example
<pre class="example"> [A, B, C] = arrayfun (@find, [10; 0], "UniformOutput", false)
A =
{
[1,1] = 1
[2,1] = [](0x0)
}
B =
{
[1,1] = 1
[2,1] = [](0x0)
}
C =
{
[1,1] = 10
[2,1] = [](0x0)
}
</pre>
<p>If the parameter <var>errfunc</var> after a further string input argument
"ErrorHandler" is another string, a function handle, an inline
function or an anonymous function, then <var>errfunc</var> defines a
function to call in the case that <var>func</var> generates an error.
The definition of the function must be of the form
<pre class="example"> function [...] = errfunc (<var>s</var>, ...)
</pre>
<p>where there is an additional input argument to <var>errfunc</var>
relative to <var>func</var>, given by <var>s</var>. This is a structure with
the elements "identifier", "message" and "index", giving
respectively the error identifier, the error message and the index of
the array elements that caused the error. The size of the output
argument of <var>errfunc</var> must have the same size as the output
argument of <var>func</var>, otherwise a real error is thrown. For
example
<pre class="example"> function y = ferr (s, x), y = "MyString"; endfunction
arrayfun (@str2num, [1234], \
"UniformOutput", false, "ErrorHandler", @ferr)
ans =
{
[1,1] = MyString
}
</pre>
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dcellfun.html#doc_002dcellfun">cellfun</a>, <a href="doc_002dspfun.html#doc_002dspfun">spfun</a>, <a href="doc_002dstructfun.html#doc_002dstructfun">structfun</a>.
</p></blockquote></div>
<!-- ./DLD-FUNCTIONS/bsxfun.cc -->
<p><a name="doc_002dbsxfun"></a>
<div class="defun">
— Loadable Function: <b>bsxfun</b> (<var>f, a, b</var>)<var><a name="index-bsxfun-1312"></a></var><br>
<blockquote><p>Applies a binary function <var>f</var> element-wise to two matrix arguments
<var>a</var> and <var>b</var>. The function <var>f</var> must be capable of accepting
two column vector arguments of equal length, or one column vector
argument and a scalar.
<p>The dimensions of <var>a</var> and <var>b</var> must be equal or singleton. The
singleton dimensions of the matrices will be expanded to the same
dimensionality as the other matrix.
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002darrayfun.html#doc_002darrayfun">arrayfun</a>, <a href="doc_002dcellfun.html#doc_002dcellfun">cellfun</a>.
</p></blockquote></div>
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