在Powershell中合并2个CSV文件 [英] Merge 2 csv files in powershell

问题描述

我有2个csv文件，我想从文件A到文件B的新列添加到新文件. Atm，它不采用A中的值.

I have 2 csv files, I want to add a new column from file A to file B to a new file. Atm, It doesn't take the values from A.

文件A.csv

ID    Name

1     Peter

2     Dalas

文件B.CSV

Class

Math

Physic

新文件将是:

ID    Name   Class

1     Peter  Math

2     Dalas  Physics

两个文件的行数相同.

作为下面我正在使用的代码，我现在想如何从文件A中获取值并将其放入文件B中.

As the following the code I'm using, I would like to now how to take the values from file A and put it in file B.

$CSV1 = Import-Csv ".\A.csv"
$CSV2 = Import-Csv ".\B.csv"


$CSV1 | ForEach-Object {
  $Value= $_
  $CSV2 | Select-Object *, @{Name='Information';Expression={ $Value}}

} | Export-Csv "C.csv" -NoTypeInformation

推荐答案

假定您的两个CSV文件正确对齐(例如，您要基于它们的行号合并数据，并且不通过其他任何键进行链接)，建议以下内容:

Assuming that your two CSV files are correctly aligned (e.g you want to merge the data based on their row numbers and aren't linking by any other key) I suggest the following:

$CSV1 = Import-Csv ".\A.csv"
$CSV2 = Import-Csv ".\B.csv"

$CSV1 | ForEach-Object -Begin {$i = 0} {  
    $_ | Add-Member -MemberType NoteProperty -Name 'Class' -Value $CSV2[$i++].Class -PassThru 
} | Export-Csv "C.csv" -NoTypeInformation

说明:

• 使用-Begin脚本块将计数器设置为0(您可以在ForEach-Object之前执行此操作，但使用-Begin可以将其目的很好地链接到代码块).
• 使用Add-Member在CSV2中的每一行上使用CSV2中的行的Array索引(并像在++中那样增加该索引)，将'Class'属性添加到CSV1中的每一行.
• 使用-PassThru开关将对象返回到管道.

• Uses a -Begin script block to set a counter to 0 (you could do this before the ForEach-Object but using -Begin nicely links its purpose to the code block).
• Uses Add-Member to add the 'Class' property to each line in CSV1, using the Array index of the line in CSV2 (and incrementing that index as it does it with ++).
• Uses the -PassThru switch to return the object to the pipeline.

如果您想以另一种方式(B> A)进行操作，则可以采用相同的方法，但是需要这样做:

If you want to do it the other way around (B > A) you could take the same approach but would need to do it like this:

$CSV2 | ForEach-Object -Begin {$i = 0} {
    $CSV1[$i++] | Add-Member -MemberType NoteProperty -Name 'Class' -Value $_.Class -PassThru 
} | Export-Csv "C.csv" -NoTypeInformation

实际上我很惊讶$_.Class仍然可以像新管道的另一端一样工作，但是似乎可以.

I'm actually surprised $_.Class still works as its the other side of a new pipeline but it seems to.

您还可以像最初计划的那样使用计算表达式，但是由于额外的管道，您确实需要使用额外的变量来存储$Class:

You can also use a calculated expression like you originally planned to, but then you do need to use an extra variable to store $Class due to the extra pipeline:

$CSV2 | ForEach-Object -Begin {$i = 0} {
    $Class = $_.Class
    $CSV1[$i++] | Select @{Name='Class';Expression={$Class}},*
} | Export-Csv "C.csv" -NoTypeInformation

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