I am trying to use Powershell to replace a semicolon ; with a pipe | that is in a file that is semicolon separated, so it's a specific set of semicolons that occurs between double-quotes ". Here's a sample of the file with the specific portion in bold:
Camp;Brazil;AI;BCS GRU;;MIL-32011257;172-43333640;;"1975995;1972871;1975";FAC0088/21;3;20.000;24.8;25.000;.149;GLASSES SPARE PARTS,;EXW;C;.00;EUR;
I've tried using -replace, as follows:
(Get-Content $file.PSPath) |
Foreach-Object { $_ -replace '".*(;).*"',"|" } |
However, the regex does not replace the semicolon between the quotes with a pipe. I've tried several other Regex to no avail. What would I do to accomplish this?
You can use a Regex.Replace method with a callback as the replacement argument:
$s = 'Camp;Brazil;AI;BCS GRU;;MIL-32011257;172-43333640;;"1975995;1972871;1975";FAC0088/21;3;20.000;24.8;25.000;.149;GLASSES SPARE PARTS,;EXW;C;.00;EUR;'
$rx = [regex]'"[^"]*"'
$rx.Replace($s, { param($m) $m.value.Replace(';','|') })
# => Camp;Brazil;AI;BCS GRU;;MIL-32011257;172-43333640;;"1975995|1972871|1975";FAC0088/21;3;20.000;24.8;25.000;.149;GLASSES SPARE PARTS,;EXW;C;.00;EUR;
That is, match any substring between two " chars, and replace all ; chars with | inside the matches only.
Also, here is PowerShell Core v6.1+ version where you can pass a script block as the -replace replacement operand where the match is represented as an automatic $_ variable:
(Get-Content $file.PSPath) |
Foreach-Object { $_ -replace '"[^"]*"', { $_.Value.Replace(';', '|') } }
Why not use lookarounds?
Since the left- and right-hand delimiters are identical single chars, ", any lookaround-based solution will either be erroneous or too long and still prone to errors. It would happen because lookarounds do not consume the texts they match, and each " thus could be matched separately as the initial ". Have a look at the (?<="[^"]*);(?=[^"]*") regex, where "b;c;d";1;23;"45;677777;z" turns into "b|c|d"|1|23|"45|677777|z" because the ; between 1 and 23, and 23 and " are found between two double quotation marks.
Similar problem is also with the \G-based patterns that can be used to match multiple match occurrences between two different delimiters, and that are usually not used in .NET regex as the latter supports infinite-width lookbehinds.
Related
I have an exe output in form
Compression : CCITT Group 4
Width : 3180
and try to extract CCITT Group 4 to $var with PowerShell script
$var = [regex]::match($exeoutput,'Compression\s+:\s+([\w\s]+)(?=\n)').Groups[1].Value
The http://regexstorm.net/tester say, the regexp Compression\s+:\s+([\w\s]+)(?=\n) is correct but not PowerShell. PowerShell does not match. How can I write the regexp correctly?
You want to get all text from some specific pattern till the end of the line. So, you do not even need the lookahead (?=\n), just use .+, because . matches any char but a newline (LF) char:
$var = [regex]::match($exeoutput,'Compression\s+:\s+(.+)').Groups[1].Value
Or, you may use a -match operator and after the match is found access the captured value using $matches[1]:
$exeoutput -match 'Compression\s*:\s*(.+)'
$var = $matches[1]
Wiktor Stribiżew's helpful answer simplifies your regex and shows you how to use PowerShell's -match operator as an alternative.
Your follow-up comment about piping to Out-String fixing your problem implies that your problem was that $exeOutput contained an array of lines rather than a single, multiline string.
This is indeed what happens when you capture the output from a call to an external program (*.exe): PowerShell captures the stdout output lines as an array of strings (the lines without their trailing newline).
As an alternative to converting array $exeOutput to a single, multiline string with Out-String (which, incidentally, is slow[1]), you can use a switch statement to operate on the array directly:
# Stores 'CCITT Group 4' in $var
$var = switch -regex ($exeOutput) { 'Compression\s+:\s+(.+)' { $Matches[1]; break } }
Alternatively, given the specific format of the lines in $exeOutput, you could leverage the ConvertFrom-StringData cmdlet, which can perform parsing the lines into key-value pairs for you, after having replaced the : separator with =:
$var = ($exeoutput -replace ':', '=' | ConvertFrom-StringData).Compression
[1] Use of a cmdlet is generally slower than using an expression; with a string array $array as input, you can achieve what $array | Out-String does more efficiently with $array -join "`n", though note that Out-String also appends a trailing newline.
I need to strip out a UNC fqdn name down to just the name or IP depending on the input.
My examples would be
\\tom.overflow.corp.com
\\123.43.234.23.overflow.corp.com
I want to end up with just tom or 123.43.234.23
I have the following code in my array which is striping out the domain name perfect, but Im still left with \\tom
-Split '\.(?!\d)')[0]
Your regex succeeds in splitting off the tokens of interest in principle, but it doesn't account for the leading \\ in the input strings.
You can use regex alternation (|) to include the leading \\ at the start as an additional -split separator.
Given that matching a separator at the very start of the input creates an empty element with index 0, you then need to access index 1 to get the substring of interest.
In short: The regex passed to -split should be '^\\\\|\.(?!\d)' instead of '\.(?!\d)', and the index used to access the resulting array should be [1] instead of [0]:
'\\tom.overflow.corp.com', '\\123.43.234.23.overflow.corp.com' |
ForEach-Object { ($_ -Split '^\\\\|\.(?!\d)')[1] }
The above yields:
tom
123.43.234.23
Alternatively, you could remove the leading \\ in a separate step, using -replace:
'\\tom.overflow.corp.com', '\\123.43.234.23.overflow.corp.com' |
ForEach-Object { ($_ -Split '\.(?!\d)')[0] -replace '^\\\\' }
Yet another alternative is to use a single -replace operation, which does not require a ForEach-Object call (doesn't require explicit iteration):
'\\tom.overflow.corp.com', '\\123.43.234.23.overflow.corp.com' -replace
'?(x) ^\\\\ (.+?) \.\D .+', '$1'
Inline option (?x) (IgnoreWhiteSpace) allows you to make regexes more readable with insignificant whitespace: any unescaped whitespace can be used for visual formatting.
^\\\\ matches the \\ (escaped with \) at the start (^) of each string.
(.+?) matches one or more characters lazily.
\.\D matches a literal . followed by something other than a digit (\d matches a digit, \D is the negation of that).
.+ matches one or more remaining characters, i.e., the rest of the input.
$1 as the replacement operand refers to what the 1st capture group ((...)) in the regex matched, and, given that the regex was designed to consume the entire string, replaces it with just that.
I'm stealing Lee_Daileys $InSTuff
but appending a RegEx I used recently
$InStuff = -split #'
\\tom.overflow.corp.com
\\123.43.234.23.overflow.corp.com
'#
$InStuff |ForEach-Object {($_.Trim('\\') -split '\.(?!\d{1,3}(\.|$))')[0]}
Sample Output:
tom
123.43.234.23
As you can see here on RegEx101 the dots between the numbers are not matched
The Select-String function uses regex and populates a MatchInfo object with the matches (which can then be queried).
The regex "(\.?\d+)+|\w+" works for your particular example.
"\\tom.overflow.corp.com", "\\123.43.234.23.overflow.corp.com" |
Select-String "(\.?\d+)+|\w+" | % { $_.Matches.Value }
while this is NOT regex, it does work. [grin] i suspect that if you have a really large number of such items, then you will want a regex. they do tend to be faster than simple text operators.
this will get rid of the leading \\ and then replace the domain name with .
# fake reading in a text file
# in real life, use Get-Content
$InStuff = -split #'
\\tom.overflow.corp.com
\\123.43.234.23.overflow.corp.com
'#
$DomainName = '.overflow.corp.com'
$InStuff.ForEach({
$_.TrimStart('\\').Replace($DomainName, '')
})
output ...
tom
123.43.234.23
I am working on a script that will generate AD usernames based off of a csv file. Right now I have the following line working.
Select-Object #{n=’Username’;e={$_.FirstName.ToLower() + $_.LastName.ToLower() -replace "[^a-zA-Z]" }}
As of right now this takes the name and combines it into a AD friendly name. However I need to name to be shorted to no more than 20 characters. I have tried a few different methods to shorten the username but I haven't had any luck.
Any ideas on how I can get the username shorted?
Probably the most elegant approach is to use a positive lookbehind in your replacement:
... -replace '(?<=^.{20}).*'
This expression matches the remainder of the string only if it is preceded by 20 characters at the beginning of the string (^.{20}).
Another option would be a replacement with a capturing group on the first 20 characters:
... -replace '^(.{20}).*', '$1'
This captures at most 20 characters at the beginning of the string and replaces the whole string with just the captured group ($1).
$str[0..19] -join ''
e.g.
PS C:\> 'ab'[0..19]
ab
PS C:\> 'abcdefghijklmnopqrstuvwxyz'[0..19] -join ''
abcdefghijklmnopqrst
Which I would try in your line as:
Select-Object #{n=’Username’;e={(($_.FirstName + $_.LastName) -replace "[^a-z]").ToLower()[0..19] -join '' }}
([a-z] because PowerShell regex matches are case in-senstive, and moving .ToLower() so you only need to call it once).
And if you are using Strict-Mode, then why not check the length to avoid going outside the bounds of the array with the delightful:
$str[0..[math]::Min($str.Length, 19)] -join ''
To truncate a string in PowerShell, you can use the .NET String::Substring method. The following line will return the first $targetLength characters of $str, or the whole string if $str is shorter than that.
if ($str.Length -gt $targetLength) { $str.Substring(0, $targetLength) } else { $str }
If you prefer a regex solution, the following works (thanks to #PetSerAl)
$str -replace "(?<=.{$targetLength}).*"
A quick measurement shows the regex method to be about 70% slower than the substring method (942ms versus 557ms on a 200,000 line logfile)
I'm trying to replace a word to some php code
$filecontent = [regex]::Replace($filecontent, $myword, $phpcode)
But the $phpcode have some php code using also a Special variable $_
<?php $cur_author = (isset($_GET['author_name'])) ? get_user_by('slug', $author_name) : get_userdata(intval($author)); ?>
The problem is when the code is replace in $filecontent it replaces the $_ variable from the php code ( $_GET ) with it have on the pipeline.
This not happen with the other variables like $author_name .
How can I resolve this?
Does this work for you?
$filecontent = [regex]::Replace($filecontent, $myword, {$phpcode})
In a regex replace operation the $_ is a reserved substituion pattern that represents the entire string
http://msdn.microsoft.com/en-us/library/az24scfc.aspx
Wrapping it in braces makes it a scriptblock delegate, bypassing the normal regex pattern matching algorithms for doing the replacement.
You have two options. First use a single quoted string and PowerShell will treat that as a verbatim string (C# term) i.e. it won't try to string interpolate:
'$_ is passed through without interpretation'
The other option is to escape the $ character in a double quoted string:
"`$_ is passed through without interpretation"
When I'm messing with a regex I will default to using single quoted strings unless I have a variable that needs to be interpolated inside the string.
Another possibility is that $_ is being interpreted by regex as a substitution group in which case you need to use the substitution escape on the $ e.g. $$.
Im not sure I am following you correctly, but does this help?
$file = path to your file
$oldword = the word you want to replace
$newword = the word you want to replace it with
If the Oldword you are replacing has special charactes ( ie. \ or $ ) then you must escape them first. You can escape them by putting a backslash in front of the special character. The Newword, does not need to be escaped. A $ would become "\$".
(get-content $file) | foreach-object {$_ -replace $oldword,$NewWord} | Set-Content $file
I am trying to use regular expressions to match certain lines in a file, but I am having some trouble.
The file contains text like this:
Mario, 123456789
Luigi, 234-567-890
Nancy, 345 5666 77533
Bowser, 348759823745908732589
Peach, 534785
Daisy, 123-456-7890
I'm trying to match just the numbers as either XXX-XXX-XXX or XXX XXX XXX pattern.
I've tried a few different ways, but it always expects something I don't want it to or it tell me everything is false.
I'm using PowerShell to do this.
At first I tried:
{$match = $i -match "\d{3}\-\d{3}\-\d{3}|\d{3}\ \d{3}\ \d{3}"
Write-Host $match}
But when I do that it matches the long strong of numbers and XXX-XXX-XXXXX.
I read something saying that n would match the exact quantity, so I tried that...
{$match = $i -match "\d{n3}\-\d{n3}\-\d{n3}|\d{n3}\ \d{n3}\ \{n3}"
Write-Host $match}
That made everything false...
So I tried
{$match = $i -match "\d\n{3}\-\d\n{3}\-\d\n{3}|\d\n{3}\ \d\n{3}\ \d\n{3}"
I also tried the lazy quantifier, ?:
{$match = $i -match "\d{3?}\-\d{3?}\-\d{3?}|\d{3?}\ \{3?}\ \{3?}"
Write-Host $match}
Still false...
The final thing I tried was this...
{$match = $i -match "\d[0-9\{3\}\-\d[0-9]\{3\}\-\d[0-9]{3\}|\d[0-9]\{3\}\ \d[0-9]\{3}\ \d[0-9]\{3\}"<br>
Write-Host $match}
Still no luck...
The following pattern gives two matches:
Get-Content .\test.txt | Where-Object {$_ -match '\d{3}[-|\s]\d{3}[-|\s]\d{3}'}
Luigi, 234-567-890
Daisy,
123-456-7890
If you want to exclude the last match, add the '$' anchor (represents the end of the string:
Get-Content .\test.txt | Where-Object {$_ -match '\d{3}[-|\s]\d{3}[-|\s]\d{3}$'}
Luigi, 234-567-890
If you want to be very specific and match lines from start to end (use the ^ anchor, denotes the start of the string):
Get-Content .\test.txt | Where-Object {$_ -match '^\w+,\s+\d{3}[-|\s]\d{3}[-|\s]\d{3}$'}
Luigi, 234-567-890
Your first answer is the closest. The {3} matches exactly 3 characters. I think the n you saw was supposed to represent any number, not an actual n character. The reason it matches the long strings is that you only specified that the match must find 3 digits, dash or space, 3 digits, dash or space, then 3 more digits. You did not specify that it doesn't count if there are more digits after that.
To not match when there is a number after, you can use a negative lookahead.
(\d{3}-\d{3}-\d{3}|\d{3}\ \d{3}\ \d{3})(?!\d)
Alternatively, if you want to only match at the end of the line, possibly with trailing space
(\d{3}-\d{3}-\d{3}|\d{3}\ \d{3}\ \d{3})\s*$
As Gideon said, your first is the best place to start.
"\b\d{3}\-\d{3}\-\d{3}\b|\b\d{3}\ \d{3}\ \d{3}\b"
The \b special character added before and after each statement is a word boundary - basically a space or newline or punctuation like a period or comma. This ensures that 9999 doesn't match, but 999. does.
Try this:
/(\d+[- ])+\d+/
It's better not to have so rigid regular expressions, unless you are absolutely sure there that your input will not change.
So this regex matches at least a digit, then greedily searches for more digits followed by a space or a dash. This is also repeated as much as possible then followed by at least another digit.
When manipulating data in PowerShell, it usually is a good idea to create objects representing the data (after all, PowerShell is all about objects). Filtering based on object properties is usually easier and more robust. Your problem is a good example.
Here is what we are after:
the persons: $persons
where: where
the number of that person: $_.number
matches: -match
the pattern
starting with three digits: ^\d{3}
followed by three digits between dashes or spaces: (-\d{3}-|\ \d{3}\ )
ending on three digits: \d{3}$
Below is the entire script:
$persons = import-csv -Header "name", "number" -delimiter "," data.csv
$persons | where {$_.number -match "^\d{3}(\-\d{3}\-|\ \d{3}\ )\d{3}$"}
You can also use Select-String:
Select-String '(\d{3}[ -]){2}\d{3}$' .\file.txt | % {$_.Line}