如何在PowerShell中的正则表达式中使用条件语句? [英] How to use a conditional statement with regex in PowerShell?

问题描述

大约有十行数据.对于每行数据，我想指出该行是否包含数字.

There are about ten lines of data. For each line of data I want to indicate whether that line contains numerals.

我如何为每一行打印出是的，这行有数字"或否，这行没有数字"，准确地打印一次?

How can I print out "yes, this line has numerals" or "no, this line has no numerals" for each and every line, exactly once?

输出:

thufir@dur:~/flwor/csv$ 
thufir@dur:~/flwor/csv$ pwsh import.ps1 
no digits

Name
----                                                                           
people…                                                                        

thufir@dur:~/flwor/csv$ 

代码:

$text = Get-Content -Raw ./people.csv
[array]::Reverse($text)

$tempAttributes = @()
$collectionOfPeople = @()

ForEach ($line in $text) { 
  if($line -notmatch '.*?[0-9].*?') {
    $tempAttributes += $line 
    Write-Host "matches digits"   
  }
  else {
    Write-Host "no digits"   
    $newPerson = [PSCustomObject]@{
      Name       = $line
      Attributes = $tempAttributes
    }
    $tempAttributes = @()
    $collectionOfPeople += $newPerson
  }
}

$collectionOfPeople

数据:

people
joe
phone1
phone2
phone3
sue
cell4
home5
alice
atrib6
x7
y9
z10

我打印数字"或无数字"的唯一原因是作为标记，以帮助构建对象.

The only reason I'm printing "digits" or "no digits" is as a marker to aid in building the object.

推荐答案

您可以使用以下内容:

switch -regex -file people.csv {
    '\d' { "yes" ; $_ }
    default { "no"; $_ }
}

\d是与数字匹配的正则表达式字符.带-regex的switch语句允许将正则表达式用于匹配文本.如果不满足其他条件，则选择default条件. $_是当前正在处理的行.

\d is a regex character matching a digit. A switch statement with -regex allows for regex expressions to be used for matching text. The default condition is picked when no other condition is met. $_ is the current line being processed.

switch通常比Get-Content快.由于您确实希望每行执行某些操作，因此您可能不想使用-Raw参数，因为该参数会将所有文件内容读取为一个字符串.

switch is generally faster than Get-Content for line by line processing. Since you do want to perform certain actions per line, you likely don’t want to use the -Raw parameter because that will read in all file contents as one single string.

# For Reverse Output
$output = switch -regex -file people.csv {
    '\d' { "yes" ; $_ }
    default { "no"; $_ }
}
$output[($output.GetUpperBound(0))..0)]

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