Regular expression seems not to work in Where-Object cmdlet - regex
I am trying to add quote characters around two fields in a file of comma separated lines. Here is one line of data:
1/22/2018 0:00:00,0000000,001B9706BE,1,21,0,1,0,0,0,0,0,0,0,0,0,0,13,0,1,0,0,0,0,0,0,0,0,0,0
which I would like to become this:
1/22/2018 0:00:00,"0000000","001B9706BE",1,21,0,1,0,0,0,0,0,0,0,0,0,0,13,0,1,0,0,0,0,0,0,0,0,0,0
I began developing my regular expression in a simple PowerShell script, and soon I have the following:
$strData = '1/29/2018 0:00:00,0000000,001B9706BE,1,21,0,1,0,0,0,0,0,0,0,0,0,0,13,0,1,0,0,0,0,0,0,0,0,0,0'
$strNew = $strData -replace "([^,]*),([^,]*),([^,]*),(.*)",'$1,"$2","$3",$4'
$strNew
which gives me this output:
1/29/2018 0:00:00,"0000000","001B9706BE",1,21,0,1,0,0,0,0,0,0,0,0,0,0,13,0,1,0,0,0,0,0,0,0,0,0,0
Great! I'm all set. Extend this example to the general case of a file of similar lines of data:
Get-Content test_data.csv | Where-Object -FilterScript {
$_ -replace "([^,]*),([^,]*),([^,]*),(.*)", '$1,"$2","$3",$4'
}
This is a listing of test_data.csv:
1/29/2018 0:00:00,0000000,001B9706BE,1,21,0,1,0,0,0,0,0,0,0,0,0,0,13,0,1,0,0,0,0,0,0,0,0,0,0
1/29/2018 0:00:00,104938428,0016C4C483,1,45,0,1,0,0,0,0,0,0,0,0,0,0,35,0,1,0,0,0,0,0,0,0,0,0,0
1/29/2018 0:00:00,104943875,0016C4B0BC,1,31,0,1,0,0,0,0,0,0,0,0,0,0,25,0,1,0,0,0,0,0,0,0,0,0,0
1/29/2018 0:00:00,104948067,0016C4834D,1,33,0,1,0,0,0,0,0,0,0,0,0,0,23,0,1,0,0,0,0,0,0,0,0,0,0
This is the output of my script:
1/29/2018 0:00:00,0000000,001B9706BE,1,21,0,1,0,0,0,0,0,0,0,0,0,0,13,0,1,0,0,0,0,0,0,0,0,0,0
1/29/2018 0:00:00,104938428,0016C4C483,1,45,0,1,0,0,0,0,0,0,0,0,0,0,35,0,1,0,0,0,0,0,0,0,0,0,0
1/29/2018 0:00:00,104943875,0016C4B0BC,1,31,0,1,0,0,0,0,0,0,0,0,0,0,25,0,1,0,0,0,0,0,0,0,0,0,0
1/29/2018 0:00:00,104948067,0016C4834D,1,33,0,1,0,0,0,0,0,0,0,0,0,0,23,0,1,0,0,0,0,0,0,0,0,0,0
I have also tried this version of the script:
Get-Content test_data.csv | Where-Object -FilterScript {
$_ -replace "([^,]*),([^,]*),([^,]*),(.*)", "`$1,`"`$2`",`"`$3`",$4"
}
and obtained the same results.
My simple test script has convinced me that the regex is correct, but something happens when I use that regex inside a filter script in the Where-Object cmdlet.
What simple, yet critical, detail am I overlooking here?
Here is my PSVerion:
Major Minor Build Revision
----- ----- ----- --------
5 0 10586 117
You're misunderstanding how Where-Object works. The cmdlet outputs those input lines for which the -FilterScript expression evaluates to $true. It does NOT output whatever you do inside that scriptblock (you'd use ForEach-Object for that).
You don't need either Where-Object or ForEach-Object, though. Just put Get-Content in parentheses and use that as the first operand for the -replace operator. You also don't need the 4th capturing group. I would recommend anchoring the expression at the beginning of the string, though.
(Get-Content test_data.csv) -replace '^([^,]*),([^,]*),([^,]*)', '$1,"$2","$3"'
This seems to work here. I used ForEach-Object to process each record.
Get-Content test_data.csv |
ForEach-Object { $_ -replace "([^,]*),([^,]*),([^,]*),(.*)", '$1,"$2","$3",$4' }
This also seems to work. Uses the ? to create a reluctant (lazy) capture.
Get-Content test_data.csv |
ForEach-Object { $_ -replace '(.*?),(.*?),(.*?),(.*)', '$1,"$2","$3",$4' }
I would just make a small change to what you have in order for this to work. Simply change the script to the following, noting that I changed the -FilterScript to a ForEach-Object and fixed a minor typo that you had on the last item in the regular expression with the quotes:
Get-Content c:\temp\test_data.csv | ForEach-Object {
$_ -replace "([^,]*),([^,]*),([^,]*),(.*)", "`$1,`"`$2`",`"`$3`",`"`$4"
}
I tested this with the data you provided and it adds the quotes to the correct columns.
Related
How can i replace all lines in a file with a pattern using Powershell?
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Based on your comment, the token 'add key="Address"' should be changed for just 'key="Address"' then the concatenating logic to build your regex looks good. You need to use the -NotMatch switch so it matches anything but those values. Also, Select-String can read files, so, Get-Content can be removed. Note, the use of (...) in this case is important because you're reading and writing to the same file in the same pipeline. Wrapping the statement in parentheses ensure that all output from Select-String is consumed before passing it through the pipeline. Otherwise, you would end up with an empty file. $values = 'key="FirstName"', 'key="Lastname"', 'key="Address"' $regexValues = [string]::Join('|', $values) (Select-String D:\test\testfile.txt -Pattern $regexValues -NotMatch) | ForEach-Object Line | Set-Content D:\test\testfile.txt Outputs: key="Id" value=123" key="ReferenceNo" value=765
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I have been trying to extract certain values from multiple lines inside a .txt file with PowerShell. Host Class INCLUDE vmware:/?filter=Displayname Equal "server01" OR Displayname Equal "server02" OR Displayname Equal "server03 test" This is what I want : server01 server02 server03 test I have code so far : $Regex = [Regex]::new("(?<=Equal)(.*)(?=OR") $Match = $Regex.Match($String)
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An alterative reading the file directly with Select-String using Wiktor's good RegEx: Select-String -Path .\file.txt -Pattern '(?<=Equal\s*")[^"]+' -AllMatches| ForEach-Object{$_.Matches.Value} | Set-Content NewFile.txt Sample output: > Get-Content .\NewFile.txt server01 server02 server03 test
Powershell replace lines stating with given pattern
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Split the string at semicolons, remove element starting with a #, then join the result back to a string. ((Get-Content $HOME/path/to/config.txt -Raw).Replace("`r`n","") -split ';' | Where-Object { $_.Trim() -notlike '#*' }) -join ';'
This might be identical to some of the other responses, but here is how I would do it: $Data = Get-Content $HOME/path/to/config.txt -Raw (($Data -split(';')).replace("`r`n",'') | Where-Object { $_ -notlike '^#*' }) -join(';') Anyway you do it, remember that rn needs to be expanded, so it has to be encased in double quotes, unlike the rest of your characters.
#############solution 1 with convertfrom-string#################### #short version (gc "$HOME/path/to/config.txt" | ? {$_ -notlike "#*"} | cfs -D ";").P1 -join ";" #verbose version (Get-Content "$HOME/path/to/config.txt" | where {$_ -notlike "#*"} | ConvertFrom-String -Delimiter ";").P1 -join ";" #############Solution 2 with convertfrom-csv####################### (Get-Content "C:\temp\test\config.txt" | where {$_ -notlike "#*"} | ConvertFrom-csv -Delimiter ";" -Header "P1").P1 -join ";" #############Solution 3 with split ####################### (Get-Content "C:\temp\test\config.txt" | where {$_ -notlike "#*"} | %{$_.Split(';')[0]}) -join ";"
replace thousands separators in csv with regex
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Tony Hinkle's comment is the answer: don't use regex for this (at least not directly on the CSV file). Your CSV is valid, so you should parse it as such, work on the objects (change the text if you want), then write a new CSV. Import-Csv -Path .\my.csv | ForEach-Object { $_ | ForEach-Object { $_ -replace ',','' } } | Export-Csv -Path .\my_new.csv (this code needs work, specifically the middle as the row will have each column as a property, not an array, but a more complete version of your CSV would make that easier to demonstrate)
You can try with this regex: ,(?=(\d{3},?)+(?:\.\d{1,3})?") See Live Demo or in powershell: % {$_ -replace ',(?=(\d{3},?)+(?:\.\d{1,3})?")','' } But it's more about the challenge that regex can bring. For proper work, use #briantist answer which is the clean way to do this.
I would use a simpler regex, and use capture groups instead of the entire capture. I have tested the follow regular expression with your input and found no issues. % {$_ -replace '([\d]),([\d])','$1$2' } eg. Find all commas with a number before and after (so that the weird mixed splits dont matter) and replace the comma entirely. This would have problems if your input has a scenario without that odd mixing of quotes and no quotes.
Regex replace contents of file and delete lines that don't match
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The best way is to remove the else clause altogether. If you do that, then no object will be returned from that iteration of the ForEach-Object block. cat .\file | %{ if($_ -match "..."){ $_ -replace "...", '...' } }
Just to append to briantist's answer you don't even need the loop structure. -match and -replace will function as array operators. Removing the need for the if and ForEach-Object. (Get-Content .\file) -match "..." -replace "...","..." Get-Content being the target of the alias cat