问题
I'm trying to extract text from a set of files on Windows using the Powershell (version 4):
PS > Select-String -AllMatches -Pattern <mypattern-with(capture)> -Path file.jsp | Format-Table
So far, so good. That gives a nice set of MatchInfo
objects:
IgnoreCase LineNumber Line Filename Pattern Matches
---------- ---------- ---- -------- ------- -------
True 30 ... file.jsp ... {...}
Next, I see that the captures are in the matches member, so I take them out:
PS > Select-String -AllMatches -Pattern <mypattern-with(capture)> -Path file.jsp | ForEach-Object -MemberName Matches | Format-Table
Which gives:
Groups Success Captures Index Length Value
------ ------- -------- ----- ------ -----
{...} True {...} 49 47 ...
or as list with | Format-List
:
Groups : {matched text, captured group}
Success : True
Captures : {matched text}
Index : 39
Length : 33
Value : matched text
Here's where I stop, I have no idea how to go further and obtain a list of captured group elements.
I've tried adding another | ForEach-Object -MemberName Groups
, but it seems to return the same as the above.
The closest I get is with | Select-Object -Property Groups
, which indeed gives me what I'd expect (a list of sets):
Groups
------
{matched text, captured group}
{matched text, captured group}
...
But then I'm unable to extract the captured group from each of them, I tried with | Select-Object -Index 1
I get only one of those sets.
Update: a possible solution
It seems that by adding | ForEach-Object { $_.Groups.Groups[1].Value }
I got what I was looking for, but I don't understand why - so I can't be sure I would be able to get the right result when extending this method to whole sets of files.
Why is it working?
As a side note, this | ForEach-Object { $_.Groups[1].Value }
(i.e. without the second .Groups
) gives the same result.
I'd like to add that, upon further attempts, it seems the command can be shortened by removing the piped | Select-Object -Property Groups
.
回答1:
Have a look at the following
$a = "http://192.168.3.114:8080/compierews/" | Select-String -Pattern '^http://(.*):8080/(.*)/$'
$a
is now a MatchInfo
($a.gettype()
) it contain a Matches
property.
PS ps:\> $a.Matches
Groups : {http://192.168.3.114:8080/compierews/, 192.168.3.114, compierews}
Success : True
Captures : {http://192.168.3.114:8080/compierews/}
Index : 0
Length : 37
Value : http://192.168.3.114:8080/compierews/
in the groups member you'll find what you are looking for so you can write :
"http://192.168.3.114:8080/compierews/" | Select-String -Pattern '^http://(.*):8080/(.*)/$' | % {"IP is $($_.matches.groups[1]) and path is $($_.matches.groups[2])"}
IP is 192.168.3.114 and path is compierews
回答2:
This script will grab a regex's specified capture group from a file's content and output its matches to console.
$file
is the file you want to load$cg
is capture group you want to grab$regex
is the regular expression pattern
Example file and its content to load:
C:\some\file.txt
This is the especially special text in the file.
Example Use: .\get_regex_capture.ps1 -file "C:\some\file.txt" -cg 1 -regex '\b(special\W\w+)'
Output: special text
get_regex_capture.ps1
Param(
$file=$file,
[int]$cg=[int]$cg,
$regex=$regex
)
[int]$capture_group = $cg
$file_content = [string]::Join("`r`n", (Get-Content -Raw "$file"));
Select-String -InputObject $file_content -Pattern $regex -AllMatches | % { $_.Matches.Captures } | % { echo $_.Groups[$capture_group].Value }
来源:https://stackoverflow.com/questions/33913878/how-to-get-the-captured-groups-from-select-string