与 Powershell 脚本 get-content 混淆

Question

要求用户输入名称，在名称数组 person.dat 文件中搜索名称。如果找到名字打印一个table，如果没有找到名字，打印一条错误消息并要求用户输入另一个名字。

persons.dat. 
George Nelson,56,78000.00
Mary Nathaniel,65,66300.00
Rosy Ferreira,32,39000.00

猜测这部分。

While ($true){
Write-Host $("1. Search by user name")
Write-Host  $("2. List all:)
$input = (Read-Host("Enter an option (0 to quit)"))##user will input value
#if 1 is entered (Read-Host("Enter user name"))
#if 2 is entered Print all#
#if 0 is entered quit.#

try{      ?             }

catch  { 
## If input is invalid, restart loop 
Write-host " User does not exist"    
continue
}

0{
Write-Host $("Thank you. Bye!")

这个底部将在 table 中打印所有 3 个。

$data = Get-Content "persons.dat"
$line = $null;
[String[]] $name = @();
[int16[]] $age = @();
[float[]] $salary = @();

foreach ($line in $data)
{ #Split fields into values
$line = $line -split (",")
$name += $line[0];
$age += $line[1];
$salary += $line[2];
}
Write-Host $("{0,-20} {1,7} {2,11}" -f "Name", "Age", "Salary")
Write-Host $("{0,-20} {1,7} {2,11}" -f "-----------", "---", "-----------")
for 
($nextItem=0 ; $nextItem -lt $name.length; $nextItem++)

{
$val1n = $name[$nextItem];
$val2n = $age[$nextItem]
$val3n = $salary[$nextItem]
Write-Host $("{0,-20} {1,7} {2,11:n2}" -f $val1n,
$val2n, $val3n)
}

Answer 1

这是您可以使用的一种方法，希望内联注释能帮助您理解其中的逻辑。由于您向我们展示的 persons.dat 文件是 comma-delimited，我们可以使用 ConvertFrom-Csv 将其转换为对象，这样，您就无需将输出构造为屏幕就像您正在处理那些 Write-Host 语句一样。

# Convert the file into an object
$persons = Get-Content persons.dat -Raw | ConvertFrom-Csv -Header "Name", "Age", "Salary"

function ShowMenu {
    # simple function to clear screen and show menu when called
    Clear-Host
    '1. Search by user name'
    '2. List all'
}

:outer while($true) {
    # clear screen and show menu
    ShowMenu
    while($true) {
        # ask user input
        $choice = Read-Host 'Enter an option (0 to quit)'
        # if input is 0, break the outer loop
        if(0 -eq $choice) {
            'Goodbye'
            break outer
        }
        # if input is not 1 or 2
        if($choice -notmatch '^(1|2)$') {
            'Invalid input!'
            $null = $host.UI.RawUI.ReadKey()
            # restart the inner loop
            continue
        }
        # if we are here user input was correct
        break
    }

    $show = switch($choice) {
        1 {
            # if choice was 1, ask user for a user name
            $user = Read-Host "Enter user name"
            # if user name exists in the `$persons` object
            if($match = $persons.where{ $_.Name -eq $user }) {
                # output this to `$show`
                $match
                # and exit this switch
                continue
            }
            # if user name was not found
            "$user was not found in list."
        }
        2 {
            # if input was 2, output `$persons` to `$show`
            $persons
        }
    }
    # show the object to the host
    $show | Out-Host
    # and wait for the user to press any key
    $null = $host.UI.RawUI.ReadKey()
}

与 Powershell 脚本 get-content 混淆

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