PowerShell单匹配结果时数组异常问题求助

我编写了一个自动化AD用户账户修改的脚本，用户输入部分姓氏即可匹配查找AD账户。脚本在多匹配、无匹配场景下均正常工作：多匹配时会列出每条结果的对应信息，无匹配时返回“USER NOT FOUND”提示。但仅找到1个匹配结果时会出现异常——用户姓名和UserID会被拆分为单个字符的数组，怀疑是数组构造逻辑存在问题，寻求解决建议。

场景展示 #

单匹配（异常情况） #

多匹配（正常情况） #

无匹配（正常情况） #

怀疑问题代码段 #

完整脚本代码 #

#prompt for last name (or at least portion of last name, then conver to a string with wild card for use in filter
$ticketNum = Read-Host "`nEnter the ServiceNow Ticket Number"
$lname = Read-Host "`nEnter at least the first three chars of users last name (you may enter full last name)"
$search = $lname + "*"

#Empty arrays
$ResultsArray=@("")
$ADUsersList=@("")

#add aduser properties to array, return error and exit if no user found
$ADUsersList += Get-ADUser -filter 'surname -like $search' -Properties * | select name,samaccountname,DistinguishedName,Enabled
if ($ADUsersList.count -le 1){
    Write-host "USER NOT FOUND"
    return
}

#populate a 2D array with NAM and with UserID
$ResultsArray = @(($ADUsersList.name),($ADUsersList.samaccountname),($ADUsersList.enabled))

Write-host "`t NAME `t`t`t USER ID `t`t ACCOUNT ENABLED"
#return list of found users and user ids. Preface with index number to use for selection menu
for($i=0;$i-le $ResultsArray[0].length-1;$i++){
    “[{0}] = {1} `t `t {2} `t `t {3}” -f $i,$ResultsArray[0][$i],$ResultsArray[1] [$i],$ResultsArray[2][$i] 
}

#Prompt 
$selection = (Read-Host "`nEnter number for user you want to modify") -as [uint32]

#Input validation - Only allow a valid index #.  If valid, write user selected to screen before proceeding 
if ($selection -notmatch '^[0-9]+$' -or $selection -gt $ResultsArray[0].length -or $selection -lt 0){
    Write-host "INVALID SELECTION!!!" -ForegroundColor Red
} 
else {
    Write-Host "`nYou selected user " -nonewline 
    Write-Host $ResultsArray[0][$selection] -nonewline -ForegroundColor Green
    Write-Host " with user ID a of " -nonewline 
    Write-Host $ResultsArray[1][$selection] -nonewline -ForegroundColor Green
    $proceed = Read-Host "`nProceed with disabling for Leave Of Absence? (y or n)"
    if($proceed -eq "y"){
        Write-Host "proceeding ..."
        $target = $ResultsArray[1][$selection]
        $aduser = Get-ADUser -Identity $target -Properties *
        $prepend = "DISABLED per HR for LOA ($ticketNum) - "
        $desc = $aduser.description
        $loaDesc = $prepend + $desc
        Set-ADUser -Identity $target -description $loaDesc
        Disable-ADAccount -Identity $target
    }
    else{
        Write-host "no changes will be made"
        break
    }
}

问题原因与解决建议 #

核心问题 #

1. 数组初始化错误：用$ADUsersList=@("")初始化数组，会导致数组默认包含一个空字符串，后续用+=添加查询结果时，单匹配场景下数组长度为2（空字符串+1个用户），虽不会触发无匹配判断，但会影响属性访问逻辑。
2. PowerShell属性访问特性：当集合仅含一个元素时，访问集合属性（如$ADUsersList.name）不会返回数组，而是直接返回单个字符串。此时将字符串放入数组，会被自动拆分为单个字符的数组，这就是单匹配时的异常根源。
3. Filter语法错误：原代码中用单引号包裹filter（'surname -like $search'），会导致变量$search无法被解析，查询逻辑失效。

解决方案 #

1. 修正数组初始化与查询逻辑

去掉初始空字符串，直接初始化空数组并赋值查询结果：

# 正确初始化空数组
$ResultsArray = @()
$ADUsersList = @()

# 修正Filter写法，确保变量被解析
$ADUsersList = Get-ADUser -filter "surname -like '$search'" -Properties * | select name,samaccountname,DistinguishedName,Enabled

# 无匹配判断逻辑优化
if ($ADUsersList.Count -eq 0) {
    Write-host "USER NOT FOUND"
    return
}

2. 强制属性访问返回数组

使用@()强制将属性值转换为数组，避免单元素场景下被拆分为字符：

# 强制转换为数组，保证单匹配时也返回数组类型
$ResultsArray = @(
    @($ADUsersList.name),
    @($ADUsersList.samaccountname),
    @($ADUsersList.Enabled)
)

3. 修复语法错误

原代码中$ResultsArray[1] [$i]存在空格，会导致语法错误，需改为$ResultsArray[1][$i]。

4. 可选优化：改用foreach遍历用户列表

放弃二维数组，直接遍历$ADUsersList，代码可读性更高且避免数组相关问题：

Write-host "`t INDEX `t NAME `t`t`t USER ID `t`t ACCOUNT ENABLED"
$index = 0
foreach ($user in $ADUsersList) {
    "[{0}] = {1} `t `t {2} `t `t {3}" -f $index, $user.name, $user.samaccountname, $user.Enabled
    $index++
}

内容的提问来源于stack exchange，提问作者RookieMistake