IndexOutOfRange - powershell

Question

I'm getting this error:
Array assignment failed because index '3' was out of range.
At Z:\CSP\deploys\aplicacional\teste.ps1:71 char:12
+ $UNAME[ <<<< $i]= $line
+ CategoryInfo : InvalidOperation: (3:Int32) [], RuntimeException
+ FullyQualifiedErrorId : IndexOutOfRange
I really can't find why the index end there.
$CSNAME = #(KPScript -c:GetEntryString $PASSHOME\$PASSFILE -pw:$PASS -Field:csname $SEARCH)
$UNAME = #()
$i = 0
Write-Host "Length="$CSNAME.Length
while($i -le $CSNAME.Length)
{
Write-Host "Start "$i
#$CSNAME[$i].GetType()
if ($CSNAME[0].StartsWith("OK:")) {
Write-Host "ACES $ACES does not exist" -Foreground "red"
}
if ($CSNAME[$i].StartsWith("OK:")) {
break
}
Write-Host "CSNAME="$CSNAME[$i]
$UNAME = $UNAME + $i
$UNAME = KPScript -c:GetEntryString $PASSHOME\$PASSFILE -pw:$PASS -Field:UserName -ref-csname:$CSNAME[$i]
foreach ($line in $UNAME) {
if (! ($line.StartsWith("OK:"))) {
Write-Host $i
$UNAME = $UNAME + $i
Write-Host "uname var"$i
$UNAME[$i] = $line
} else {
Write-Host "break"
break
}
}
#$UNAME[$i].GetType()
#if ($UNAME[$i].StartWith("OK:*")){
# break
#}
Write-Host "UNAME="$UNAME[$i]
#$UNAME[$i]
Write-Host "End "$i
$i += 1
Write-Host "switch"
}
Since the second while is based in the first array length and it has values, why is the it getting out of range?

Answer 1

PowerShell arrays are zero-based, so an array of length 3 has index values from 0 through 2. Your code, however, would iterate from 0 to 3, because the loop condition checks if the variable is less or equal the length (-le):
while($i -le $CSNAME.Length)
{
...
}
You need to check if the variable is less than the length (or less or equal the length minus one):
while($i -lt $CSNAME.Length)
{
...
}
Also, you'd normally use a for loop for iterating over an array, so you can handle the index variable in one place:
for ($i=0; $i -lt $CSNAME.Length; $i++) {
...
}
Edit: You initialize $UNAME as an array, but inside the loop you assign $UNAME = KPScript ..., which replaces the array with whatever the script returns (another array, a string, $null, ...). Don't use the same variable for different things in a loop. Assign the script output to a different variable. Also, your way of appending to the array is rather convoluted. Instead of $UNAME = $UNAME + $i; $UNAME[$i] = $line simply do $UNAME += $line.
$res = KPScript -c:GetEntryString $PASSHOME\$PASSFILE -pw:$PASS -Field:UserName -ref-csname:$CSNAME[$i]
foreach ($line in $res) {
if (! ($line.StartsWith("OK:"))) {
$UNAME += $line
} else {
break
}
}