<p>How do I convert function input parameters to the right type?</p>

<p>I want to return a string that has part of the URL passed into it removed.</p>

<p><strong>This works, but it uses a hard-coded string:</strong></p>

<pre><code>function CleanUrl($input)
{
    $x = "http://google.com".Replace("http://", "")
    return $x
}

$SiteName = CleanUrl($HostHeader)
echo $SiteName
</code></pre>

<p><strong>This fails:</strong></p>

<pre><code>function CleanUrl($input)
{
    $x = $input.Replace("http://", "")
    return $x
}

Method invocation failed because [System.Array+SZArrayEnumerator] doesn't contain a method named 'Replace'.
At M:\PowerShell\test.ps1:13 char:21
+     $x = $input.Replace( &lt;&lt;&lt;&lt; "http://", "")
</code></pre>

```
```
function CleanUrl([string] $url)
{
    return $url.Replace("http://", "")
}
```
```