如何通过函数 arg 传递 csv 列对象

How to pass csv column object through function arg

我有很多重复代码想要清理。我知道以下语法不正确,但你能告诉我正确的方法吗?假设我有以下代码...

Function GetColumnOneValues
{
    Param ($csvFile, $ValuesWithoutNullFile)

    Import-Csv $csvFile | Where-Object {$_.test1ColumnOne} | 
    Export-Csv $ValuesWithoutNullFile -NoTypeInformation -Force
}

Function GetColumnTwoValues
{
    Param ($csvFile, $ValuesWithoutNullFile)

    Import-Csv $csvFile | Where-Object {$_.test2ColumnTwo} | 
    Export-Csv $ValuesWithoutNullFile -NoTypeInformation -Force
}

Function GetColumnThreeValues
{
    Param ($csvFile, $ValuesWithoutNullFile)

    Import-Csv $csvFile | Where-Object {$_.test3ColumnThree} | 
    Export-Csv $ValuesWithoutNullFile -NoTypeInformation -Force
}

^注意重复代码

Function Main
{
    $test1CsvFile = "C:\Scripts\Tests\test1.csv"
    $test1CsvFileResults = "C:\Scripts\Tests\test1Results.csv"
    $test2CsvFile = "C:\Scripts\Tests\test2.csv"
    $test2CsvFileResults = "C:\Scripts\Tests\test2Results.csv"
    $test3CsvFile = "C:\Scripts\Tests\test3.csv"
    $test3CsvFileResults = "C:\Scripts\Tests\test3Results.csv"

    GetColumnOneValues $test1CsvFile $test1CsvFileResults
    GetColumnTwoValues $test2CsvFile $test2CsvFileResults
    GetColumnThreeValues $test3CsvFile $test3CsvFileResults
}

Main

相反,它应该是这样的...

Function GetColumnValues
{
    Param ($csvFile, $ValuesWithoutNullFile, $ColumnName)

    Import-Csv $csvFile | Where-Object {$ColumnName} | 
    Export-Csv $ValuesWithoutNullFile -NoTypeInformation -Force
}

Function Main
{
    $test1CsvFile = "C:\Scripts\Tests\test1.csv"
    $test1CsvFileResults = "C:\Scripts\Tests\test1Results.csv"
    $test2CsvFile = "C:\Scripts\Tests\test2.csv"
    $test2CsvFileResults = "C:\Scripts\Tests\test2Results.csv"
    $test3CsvFile = "C:\Scripts\Tests\test3.csv"
    $test3CsvFileResults = "C:\Scripts\Tests\test3Results.csv"

    $column1 = $_.test1ColumnOne
    $column2 = $_.test2ColumnTwo
    $column3 = $_.test3ColumnThree

    GetColumnValues $test1CsvFile $test1CsvFileResults $column1
    GetColumnValues $test2CsvFile $test2CsvFileResults $column2
    GetColumnValues $test3CsvFile $test3CsvFileResults $column3
}

Main

但是,函数打印的不是非空值,而是空白的 csv 文件。

使用这些 csv 文件测试代码...

csvFile1...

test1ColumnOne,test1ColumnTwo,test1ColumnThree
qwer,,
,qwer,
,,qwer

csvFile2...

test2ColumnOne,test2ColumnTwo,test2ColumnThree
asdf,,
,asdf,
,,asdf

csvFile3...

test3ColumnOne,test3ColumnTwo,test3ColumnThree
zxcv,,
,zxcv,
,,zxcv

结果应该是...

test1Results.csv...

"test1ColumnOne","test1ColumnTwo","test1ColumnThree"
"qwer","",""

test2Results.csv...

"test2ColumnOne","test2ColumnTwo","test2ColumnThree"
"","asdf",""

test3Results.csv...

"test3ColumnOne","test3ColumnTwo","test3ColumnThree"
"","","zxcv"

不确定您听到的到底是什么,但您 GetColumnValues 所以让我们构建一个具有该目标的函数。您有一个 columnName 参数。也应该添加一个 -path

Function Get-ColumnValues{
    Param ($Path, $ColumnName)

    $csvData = Import-Csv $Path
    If($ColumnName -in ($csvData | Get-Member -MemberType "NoteProperty").Name){
        ($csvData).$ColumnName | Where-Object{![string]::IsNullOrEmpty($_)}
    } Else {
        Throw "There is no column present called $ColumnName in the file $Path" 
    }
}

这里可以包含更多的错误预防措施,但简单地说,这将导入一个 csv 和 return 所请求列的值(假设它存在)。

顺便说一句,如果您要导出结果,您的函数名称会产生误导。您不仅要获取它们,还要设置它们。

如果您想从 CSV 列中清除空值,同时保留该列的非空值列表,我会使用如下通用函数来完成:

function Remove-EmptyValues {
  Param(
    [Parameter(
      Mandatory=$true,
      Position=0,
      ValueFromPipeline=$true,
      ValueFromPipelineByPropertyName=$true
    )]
    [object[]]$Csv,
    [Parameter(Mandatory=$true, Position=1)]
    [string]$ColumnTitle
  )

  Process {
    $Csv | Select-Object -Expand $ColumnTitle | Where-Object { $_ }
  }
}

所以可以这样用

$csv = Import-Csv 'C:\testScripts\test.csv'
$noEmpty = Remove-EmptyValues $csv 'column A'

或者像这样:

$csv = Import-Csv 'C:\testScripts\test.csv'
$noEmpty = $csv | Remove-EmptyValues -ColumnTitle 'column A'

编辑: 如果要删除特定列中值为空的所有行,请将输入和输出文件名以及列名称作为字符串参数传递:

function Remove-EmptyRecords {
  Param(
    [Parameter(Mandatory=$true, Position=0)]
    [string]$Source,
    [Parameter(Mandatory=$true, Position=1)]
    [string]$Destination,
    [Parameter(Mandatory=$true, Position=2)]
    [string]$ColumnTitle
  )

  Import-Csv $Source |
    Where-Object { $_.$ColumnTitle } |
    Export-Csv $Destination -NoType
}

Remove-EmptyRecords test1.csv test1Results.csv test1ColumnOne
Remove-EmptyRecords test2.csv test2Results.csv test2ColumnTwo
Remove-EmptyRecords test3.csv test3Results.csv test3ColumnThree