<h3>strpos() function</h3>
Return the index of a regular expression in a string.

<h4>Syntax</h4>
     strpos(<i>haystack</i>, <i>needle</i>)
<br><br>
Returns -1 if the expression isn't found.

<p><h4>Arguments</h4>
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<i>  haystack</i> &rarr; is string.  The string that is to be searched.<br>
<i>  needle</i> &rarr; is string.  The regular expression to look for.<br>

<h4>Example</h4>
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     strpos('HELLO WORLD','WORLD') &rarr; 6<br>
     strpos('HELLO WORLD','GOODBYE') &rarr; -1<br>
