Regex Match any string powershell

Question

No matter how well I feel like I know regular expressions, they always seem to beat me.

I am looking for a universal pattern that will match any string. The only way I could figure out how to handle all these different naming conventions, was make a bunch of different regex patterns, and now I'm not even sure if all the data is getting picked up so I would have to manually cross-check it.

I am just trying to pick up anything that could possibly be within two brackets [ ] :

elseif($line -match "\[\w*\d*\]") {         
    $pars = $matches[0]
}
elseif($line -match "\[\d*\w*\]") {
    $pars = $matches[0]
}
elseif($line -match "\[\w*\d*_\w*\]") {
    $pars = $matches[0]
}
elseif($line -match "\[\w*\d*_*\w*-*\w*:*\w*\]") {
    $pars = $matches[0]
}            
elseif($line -match "\[\w*_*\w*_*\w*_*\w*_*\w*_*\w*-*\w*\]") {
    $pars = $matches[0]
}

The way I am doing it does not generate errors, but I am not sure it handles all the situations I could potentially come across. Checking manually is almost impossible with this much data.

Also, if anyone knows of a great utility for generating regex patterns it would be much appreciated. I have only been able to find regex testers which isn't very useful to me, and there is little help online for regular expressions with powershell.

what did you mean by any string? does that means regex .+ will do? and btw, \d and _ is already included inside \w — Angga
– Angga, Commented Aug 1, 2013 at 17:39
You don't really describe very well what exactly you're trying to match inside the brackets. From what I can infer from you're code, you're looking for any string that just has alphanumeric characters and the underscore. If that's the case, you could just use \[[\d\w]*\] or \[[a-zA-Z_0-9]*\].... Oh, I see a colon and dash in there too. Well, in that case you can do \[[\w\d:-]*\]. — Ethan Brown
– Ethan Brown, Commented Aug 1, 2013 at 18:11
Angga got it on point. By any string I meant "Any Possible characters you can place in between 2 brackets". The .+ handles that exactly. Thank you, post your solution so I can accept it as an answer — Cole9350
– Cole9350, Commented Aug 1, 2013 at 18:31
@Cole9350 It would be better to update the question with this information. — Peter Mortensen
– Peter Mortensen, Commented May 29, 2017 at 17:41
@PeterMortensen Please do not use your automated software to edit my questions / answers. The edits are not useful and do not make sense. Wikipedia is not a valid source to site for the change you suggested. — Cole9350
– Cole9350, Commented Jun 21, 2017 at 19:05

JPBlanc · Accepted Answer · 2016-04-07 17:16:09Z

21

$a = [regex]"\[(.*)\]"
$b = $a.Match("sdfqsfsf[fghfdghdfhg]dgsdfg") 
$b.Captures[0].value

edited Apr 7, 2016 at 17:16

answered Aug 1, 2013 at 18:14

JPBlanc

73k17 gold badges137 silver badges180 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Cole9350 Over a year ago

Perfect, This works just as well as .+ , which leaves me to figure out the difference between greedy and ungreedy. Thank you very much.

JPBlanc Over a year ago

Sorry I don't understand your question ?

David.Chu.ca Over a year ago

what happens if a string contains more than one ], ex "asdfasfd[asdf]sfafe]asdfs"? How to get "asdf" within [..]?

Alex Over a year ago

Use $a.Matches() instead of Match() to return multiple results - Match() seems to find one and then stop

Adrian Over a year ago

@David.Chu.ca, $a = [regex]"\[([^\[\]]*)\]" will stop it from matching against the 2nd ]

Aaron Jensen · Accepted Answer · 2013-08-01 19:20:23Z

7

Match everything that isn't a bracket. Create a character class that contains anything but the bracket characters:

$line -match "\[[^\[\]]+\]"

answered Aug 1, 2013 at 19:20

Aaron Jensen

27.2k18 gold badges85 silver badges93 bronze badges

Comments

Jithin Pavithran · Accepted Answer · 2017-05-30 03:15:40Z

2

Focusing to

"I am just trying to pick up anything that could possibly be within two brackets [ ]"

I think \[.*\] is what you are looking for.

Explanation
Sice [ and ] have special purposes, so you need to use \ before those characters.
.(dot) stands for any character and
* stands for any number of repetition of the previous charector.
Here, the previous character is ., so .* stands for any general string.

edited May 30, 2017 at 3:15

answered May 23, 2016 at 15:48

Jithin Pavithran

1,3713 gold badges20 silver badges44 bronze badges

Comments

Ryszard Czech · Accepted Answer · 2021-09-19 20:55:51Z

Matching anything between two brackets:

$text='[a[b]c] and [d text]'
$p = [regex]'\[[^][]*]'
$p.Matches($text) | % {Write-Host $_.value}

See regex proof. Results:

[b]
[d text]

EXPLANATION

--------------------------------------------------------------------------------
  \[                       '['
--------------------------------------------------------------------------------
  [^][]*                   any character except: ']', '[' (0 or more
                           times (matching the most amount possible))
--------------------------------------------------------------------------------
  ]                        ']'

If the brackets need to be paired and can be nested:

\[(?>[^][]+|(?<g>)\[|(?<-g>)])*]

See regex proof. EXPLANATION

--------------------------------------------------------------------------------
  \[                       '['
--------------------------------------------------------------------------------
  (?>                      match (and do not backtrack afterwards) (0
                           or more times (matching the most amount
                           possible)):
--------------------------------------------------------------------------------
    [^][]+                   any character except: ']', '[' (1 or
                             more times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
  (?<g>)\[                '[' (empty match added to "g" group stack)
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
  (?<-g>)]                ']' (empty match removed from "g" group stack)
--------------------------------------------------------------------------------
  )*                       end of look-ahead
--------------------------------------------------------------------------------
  ]                        ']'

Collectives™ on Stack Overflow

Regex Match any string powershell

4 Answers 4

5 Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

5 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related