You cannot call a method on a null-valued expression? - powershell

Question

I'm trying to take the input "name" and find the whitespace so that I can find the first and last letter of the first and last name entered. But it's telling me "You cannot call a method on a null-valued expression." Help?
$name = Read-Host "Please enter the zip of person $count"
$length = $name.Length
$name = $name.split(" ")
write-host $name[0]

Answer 1

You made a significant change to your post. It used to be:
$name = Read-Host "Please enter the name of person $count"
$length = $name.Length
$pos = $name.IndexOf('\s')
print $pos
Lets ignore the $length line since you do not use it. It looks like you are trying to split on the first white space using regular expressions. You are using .IndexOf() which if you examine the overloads will see it expects strings or a char. Not earth shattering but the point is it is looking for string literals and does not support regular expressions. Consider the following statements
PS C:\Users\Cameron> "John Smith".IndexOf('\s')
-1
PS C:\Users\Cameron> "John\sSmith".IndexOf('\s')
4
The first returned -1 since the string \s was not found. Then we put that string between John and Smith and we now get a positive return since the string literal was matched.
What you were possibly trying to do was use the -split which I base on your original question and the edit. -split supports regular expressions.
PS C:\Users\Cameron> $name = "John Smith"
PS C:\Users\Cameron> ($name -split '\s+')[0]
John
What the second line of code did was split the string $name on the group of white-space. We returned the first element which would be 'John'. The second, not shown since it should be obvious is 'Smith'. Neither elements have trailing or leading white-space ( based only on this example. Mileage will vary on other strings.)
Also, the command print is and alias for Out-Printer. Doubt you meant that command and were most likely looking for, like Dane Boulton suggested, Write-Host or Write-Output. Note: Look them up to understand an important difference. Former writes to console where the ladder writes to the output stream.
Lastly good guess would be that the error was caused by $name being null at the time $name.IndexOf('\s') was called. Easy to simulate as well.
PS C:\Users\Cameron> $something = $null
PS C:\Users\Cameron> $something.Method()
You cannot call a method on a null-valued expression.
At line:1 char:1
+ $something.Method()
+ ~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull

Answer 2

im not sure which is causing you to get the null value error. But to get the first and last name just use this:
$name = "John Smith"
$name = $name.split(" ")
$name[0] #outputs John
$name[1] #outputs Smith
Also you want write-host or write-output not print