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copied!<p>The <a href="https://www.mathworks.com/help/matlab/matlab_prog/creating-a-function-handle.html" rel="nofollow noreferrer">function handle operator</a> in MATLAB acts essentially like a pointer to a specific instance of a function. Some of the other answers have discussed a few of its uses, but I'll add another use here that I often have for it: maintaining access to functions that are no longer "in scope".</p> <p>For example, the following function initializes a value <code>count</code>, and then returns a function handle to a nested function <code>increment</code>:</p> <pre><code>function fHandle = start_counting(count) disp(count); fHandle = @increment; function increment count = count+1; disp(count); end end </code></pre> <p>Since the function <code>increment</code> is a <a href="https://www.mathworks.com/help/matlab/matlab_prog/nested-functions.html" rel="nofollow noreferrer">nested function</a>, it can only be used within the function <code>start_counting</code> (i.e. the workspace of <code>start_counting</code> is its "scope"). However, by returning a handle to the function <code>increment</code>, I can still use it outside of <code>start_counting</code>, and it still retains access to the variables in the workspace of <code>start_counting</code>! That allows me to do this:</p> <pre><code>>> fh = start_counting(3); % Initialize count to 3 and return handle 3 >> fh(); % Invoke increment function using its handle 4 >> fh(); 5 </code></pre> <p>Notice how we can keep incrementing count even though we are outside of the function <code>start_counting</code>. But you can do something even more interesting by calling <code>start_counting</code> again with a different number and storing the function handle in another variable:</p> <pre><code>>> fh2 = start_counting(-4); -4 >> fh2(); -3 >> fh2(); -2 >> fh(); % Invoke the first handle to increment 6 >> fh2(); % Invoke the second handle to increment -1 </code></pre> <p>Notice that these two different counters operate independently. The function handles <code>fh</code> and <code>fh2</code> point to different instances of the function <code>increment</code> with different workspaces containing unique values for <code>count</code>.</p> <p>In addition to the above, using function handles in conjunction with nested functions can also help streamline GUI design, as I illustrate in <a href="https://stackoverflow.com/a/425347/52738">this other SO post</a>.</p>

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