How do I do a string replacement in a PowerShell function? - string

Question

How do I convert function input parameters to the right type?
I want to return a string that has part of the URL passed into it removed.
This works, but it uses a hard-coded string:
function CleanUrl($input)
{
$x = "http://google.com".Replace("http://", "")
return $x
}
$SiteName = CleanUrl($HostHeader)
echo $SiteName
This fails:
function CleanUrl($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( <<<< "http://", "")

Answer 1

Steve's answer works. The problem with your attempt to reproduce ESV's script is that you're using $input, which is a reserved variable (it automatically collects multiple piped input into a single variable).
You should, however, use .Replace() unless you need the extra feature(s) of -replace (it handles regular expressions, etc).
function CleanUrl([string]$url)
{
$url.Replace("http://","")
}
That will work, but so would:
function CleanUrl([string]$url)
{
$url -replace "http://",""
}
Also, when you invoke a PowerShell function, don't use parenthesis:
$HostHeader = "http://google.com"
$SiteName = CleanUrl $HostHeader
Write-Host $SiteName
Hope that helps. By the way, to demonstrate $input:
function CleanUrls
{
$input -replace "http://",""
}
# Notice these are arrays ...
$HostHeaders = #("http://google.com","http://stackoverflow.com")
$SiteNames = $HostHeader | CleanUrls
Write-Output $SiteNames

Answer 2

The concept here is correct.
The problem is with the variable name you have chosen. $input is a reserved variable used by PowerShell to represent an array of pipeline input. If you change your variable name, you should not have any problem.
PowerShell does have a replace operator, so you could make your function into
function CleanUrl($url)
{
return $url -replace 'http://'
}

Answer 3

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

Answer 4

This worked for me:
function CleanUrl($input)
{
return $input.Replace("http://", "")
}