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.

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

73.1k17 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

Collectives™ on Stack Overflow

Regex Match any string powershell

4 Answers 4

5 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest