Removing spaces from specific columns of pipe seperated file - powershell

Question

I'm trying to remove spaces from columns 15 and 16 in a pipe seperated file.
I've tried the code at the bottom of this post after searching the web but it's failing with
You cannot call a method on a null-valued expression. At line:19
char:2
+ $.h15=$.h15.ToString().Replace(' ','')
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull
and
You cannot call a method on a null-valued expression. At line:20
char:5
+ $.h16=$.h16.ToString().Replace(' ','')
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNul
I guess from that, that it's not reading in the data but I can't see why not. I've checked the variables and they are correct.
$header = 1..42 | ForEach-Object { "h$_" }
$dialler_out_path="$dialler_file_dir\$output_file"
$dialler_path="$dialler_file_dir\$dialler_file"
(Import-Csv -Delimiter '|' -Header $header -Path $dialler_path | %{
$_.h15=$_.h15.ToString().Replace(' ','')
$_.h16=$_.h16.ToString().Replace(' ','')
}) | export-csv $dialler_out_path -NoType

Answer 1

Another way to deal with null object (in addition to comments):
$_.h15 = (-join ($_.h15)).ToString().Replace(' ','')
You should produce output in foreach:
(Import-Csv -Delimiter '|' -Header $header -Path $dialler_path | %{
$_.h15 = (-join ($_.h15)).ToString().Replace(' ','')
$_.h16 = (-join ($_.h16)).ToString().Replace(' ','')
$_
}) | export-csv $dialler_out_path -NoType