我正在创建以下脚本以搜索并替换一组文件中的数据。我遇到的问题是，我只需要在行的开始时匹配，并且在进行比较时，我不确定如何/在何处使用the Regex(例如 ^a， ^b(？我试图将套在表格的前面放在表格中，但这无效...
$lookupTable = @{
'A'='1';
'B'='2'
#etc
}
Get-ChildItem 'c:windowssystem32dns' -Filter *.dns |
Foreach-Object {
$file = $_
Write-Host "$file"
(Get-Content -Path $file -Raw) | ForEach-Object {
$line = $_
$lookupTable.GetEnumerator() | ForEach-Object {
$line = $line -replace $_.Name, $_.Value
}
$line
} | Set-Content -Path $file
}
-replace操作员接受正则。只是$line = $line -replace "^$($_.Name)", "$_.Value"。
REGEX WORK的方式使得将正确的"开始"标记与$VarName 一起进入Regex模式。因此，我将其分解为自己的行，并使用-f字符串格式运算符来构建正则表达式模式。
然后，我使用了-replace在 rarnay上工作的方式通常从Get-Content获得的字符串，以在每个通过时在整个数组上工作。
请注意，字符串在更换OTTA的地方具有较低的案例项目，并且大写项目不应更换该项目。[ grin ]
$LookUpTable = @{
A = 'Wizbang Shadooby'
Z = '666 is the number of the beast'
}
$LineList = @(
'a sdfq A er Z xcv'
'qwertyuiop A'
'z xcvbnm'
'z A xcvbnm'
'qwertyuiop Z'
)
$LookUpTable.GetEnumerator() |
ForEach-Object {
$Target = '^{0}' -f $_.Name
$LineList = $LineList -replace $Target, $_.Value
}
$LineList
输出...
Wizbang Shadooby sdfq A er Z xcv
qwertyuiop A
666 is the number of the beast xcvbnm
666 is the number of the beast A xcvbnm
qwertyuiop Z
# Here is a complete, working script that beginners can read.
# This thread
# Using regex in a key/value lookup table in powershell?
# https://stackoverflow.com/questions/57277282/using-regex-in-a-key-value-lookup-table-in-powershell
# User-modifiable variables.
# substitutions
# We need to specify what we're looking for (keys).
# We need to specify our substitutions (values).
# Example: Looking for A and substituting 1 in its place.
# Add as many pairs as you like.
# Here I use an array of objects instead of a Hashtable so that I can specify upper- and lowercase matches.
# Use the regular expression caret (^) to match the beginning of a line.
$substitutions = @(
[PSCustomObject]@{ Key = '^A'; Value = '1' },
[PSCustomObject]@{ Key = '^B'; Value = '2' },
[PSCustomObject]@{ Key = '^Sit'; Value = '[Replaced Text]' }, # Example for my Latin placeholder text.
[PSCustomObject]@{ Key = 'nihil'; Value = '[replaced text 2]' }, # Lowercase example.
[PSCustomObject]@{ Key = 'Nihil'; Value = '[Replaced Text 3]' } # Omit comma for the last array item.
)
# Folder where we are looking for files.
$inputFolder = 'C:UsersMichaelPowerShellUsing regex in a key value lookup table in powershellinput'
# Here I've created some sample files using Latin placeholder text from
# https://lipsum.com/
# Folder where we are saving the modified files.
# This can be the same as the input folder.
# I'm creating this so we can test without corrupting the original files.
$outputFolder = 'C:UsersMichaelPowerShellUsing regex in a key value lookup table in powershelloutput'
#$outputFolder = $inputFolder
# We are only interested in files ending with .dns
$filterString = '*.dns'
# Here is an example for text files.
#$filterString = '*.txt'
# For all files.
#$filterString = '*.*'
# More info.
# https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.management/get-childitem?view=powershell-6#parameters
# Search on the page for -Filter
# You won't need to update any variables after this line.
# ===================================================================
# Generate a list of files to look at.
$fileList = Get-ChildItem $inputFolder -Filter $filterString
# Simple example.
# get-content .apple.dns | % { $_ -replace "sit", "michael" } | set-content "C:outputapple.dns"
# input file substitutions output
# Set up loops.
# For each file.
#{
# For each key-value pair.
#}
# "For each key-value pair."
# Create a function.
# Pipe in a string.
# Specify a list of substitutions.
# Make the substitutions.
# Output a modified string.
filter find_and_replace ([object[]] $substitutions)
{
# The automatic variable $_ will be a line from the file.
# This comes from the pipeline.
# Copy the input string.
# This avoids modifying a pipeline object.
$myString = $_
# Look at each key-value pair passed to the function.
# In practice, these are the ones we defined at the top of the script.
foreach ($pair in $substitutions)
{
# Modify the strings.
# Update the string after each search.
# case-sensitive -creplace instead of -replace
$myString = $myString -creplace $pair.Key, $pair.Value
}
# Output the final, modified string.
$myString
}
# "For each file."
# main
# Do something with each file.
foreach ($file in $fileList)
{
# Where are we saving the output?
$outputFile = Join-Path -Path $outputFolder -ChildPath $file.Name
# Create a pipeline.
# Pipe strings to our function.
# Let the function modify the strings.
# Save the output to the output folder.
# This mirrors our simple example but with dynamic files and substitutions.
# find_and_replace receives strings from the pipeline and we pass $substitutions into it.
Get-Content $file | find_and_replace $substitutions | Set-Content $outputFile
# The problem with piping files into a pipeline is that
# by the time the pipeline gets to Set-Content,
# we only have modified strings
# and we have no information to create the path for an output file.
# ex [System.IO.FileInfo[]] | [String[]] | [String] | Set-Content ?
#
# Instead, we're in a loop that preserves context.
# And we have the opportunity to create and use the variable $outputFile
# ex foreach ($file in [System.IO.FileInfo[]])
# ex $outputFile = ... $file ...
# ex [String[]] | [String] | Set-Content $outputFile
# Quote
# (Get-Content -Path $file -Raw)
# By omitting -Raw, we get: one string for each line.
# This is instead of getting: one string for the whole file.
# This keeps us from having to use
# the .NET regular expression multiline option (and the subexpression r?$)
# while matching.
#
# What it is.
# Multiline Mode
# https://learn.microsoft.com/en-us/dotnet/standard/base-types/regular-expression-options#Multiline
#
# How you would get started.
# Miscellaneous Constructs in Regular Expressions
# https://learn.microsoft.com/en-us/dotnet/standard/base-types/miscellaneous-constructs-in-regular-expressions
}