How to subtract multiple string values from another string : <p>With:</p>

<pre><code>abc = 'abc'
xyz = 'xyz'

word = 'begin abc- middle_xyz_ end'
</code></pre>

<p>I need to extract the values of <code>abc</code> and <code>xyz</code> from <code>word</code>.
The result should be </p>

<pre><code>result = 'begin - middle__ end'
</code></pre>

<p>How to achieve this with a minimum amount of code?</p>
