Understanding Local Variables in PHP: Usage and Best Practices

A variable declared in a function is considered local; that is, it can be referenced solely in that function. Any assignment outside of that function will be considered to be an entirely different variable from the one contained in the function ?

Example:

<span class="pln">

 
</span><span class="pun">&lt;?</span><span class="pln">php
   $x </span><span class="pun">=</span><span class="pln"> </span><span class="lit">4</span><span class="pun">;</span><span class="pln">
   
   </span><span class="kwd">function</span><span class="pln"> assignValue </span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> 
      $x </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln">
      </span><span class="kwd">print</span><span class="pln"> </span><span class="str">"\$x inside function is $x. &lt;br /&gt;"</span><span class="pun">;</span><span class="pln">
   </span><span class="pun">}</span><span class="pln">
   
   assignValue</span><span class="pun">();</span><span class="pln">
   </span><span class="kwd">print</span><span class="pln"> </span><span class="str">"\$x outside of function is $x. &lt;br /&gt;"</span><span class="pun">;</span><span class="pln">
</span><span class="pun">?&gt;</span><span class="pln">

</span>

Output:

This will produce the following result -

<span class="pln">

$x inside </span><span class="kwd">function</span><span class="pln"> </span><span class="kwd">is</span><span class="pln"> </span><span class="lit">0.</span><span class="pln">
$x outside </span><span class="kwd">of</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> </span><span class="kwd">is</span><span class="pln"> </span><span class="lit">4.</span><span class="pln">

</span>