Powershell regex select portion of a string

Question

I have a string that varies

BLUE ORIGIN             CONTACT:  MB

The first part is what varies, it's basically a customer name. So the number of characters and spaces will change.

I know I can use this and it will match what I need

$String = 'BLUE ORIGIN             CONTACT:  MB'
$string -match '(^\S+\s+\S+)(\s+)(CONTACT:)(\s+)(\S+)'
$Matches[1]

But if the string changes to something like this, with no spaces

CUSTOMERNAME            CONTACT:  MB

the -match is false.

How can I do a regex that grabs the first part of the string regardless of its length or characters?

Probably wasn't super clear. The Values I am after are

$Matches[1] - In the above would be BLUE ORIGIN

$Matches[3] - CONTACT:

$Matches[5] - MB

Is the data before CONTACT: guaranteed to be fixed-length? If so, do you know what that length is? — Jeff Zeitlin
– Jeff Zeitlin, Commented Dec 13, 2018 at 18:33

jpmc26 · Accepted Answer · 2018-12-13 18:41:30Z

3

Regular expression engines usually support partial matches of strings. Don't try to match all the stuff before CONTACT:

$s = 'BLUE ORIGIN             CONTACT:  MB'
$s -match 'CONTACT:\s+(\S+)'
$Matches

Output:

Name                           Value
----                           -----
1                              MB
0                              CONTACT:  MB

(So you can just do $Matches[1] to get just the value you're after.)

If you need to break apart the whole line into several elements of data and not just this one, I don't think I'd use regular expressions. I'd look into developing a parser (syntactic analyzer). Doing that in PowerShell is probably ill-advised, though. Here are some .NET tools that might help with that.

edited Dec 13, 2018 at 18:41

answered Dec 13, 2018 at 18:34

jpmc26

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user6811411 · Accepted Answer · 2018-12-13 19:13:48Z

2

You are IMO overcomplicating things.
With placing the parentheses for the capture groups you decide what to capture.

$String = 'BLUE ORIGIN             CONTACT:  MB'
$string -match '^(.*?)\s+(CONTACT:)\s+(\S+)' | Out-Null
$matches | ft -AutoSize

Name Value
---- -----
3    MB
2    CONTACT:
1    BLUE ORIGIN
0    BLUE ORIGIN             CONTACT:  MB

$string = "CUSTOMERNAME            CONTACT:  MB"
$string -match '^(.*?)\s*(CONTACT:)\s+(\S+)'|Out-Null
$matches | ft -AutoSize

Name Value
---- -----
3    MB
2    CONTACT:
1    CUSTOMERNAME
0    CUSTOMERNAME            CONTACT:  MB

answered Dec 13, 2018 at 19:13

user6811411

1 Comment

LeeM Over a year ago

Totally agree with just matching the strings you want to capture. This seems to best represent what the OP is asking for.

The fourth bird · Accepted Answer · 2018-12-13 18:49:14Z

1

To make your regex work for both examples, you could change (^\S+\s+\S+) to (^\S+\s*\S+) making the whitespace \s* character match 0+ times instead of 1+ times.

(^\S+\s*\S+)(\s+)(CONTACT:)(\s+)(\S+)
.......^

Regex demo

You could omit the capturing group around (\s+) and just match \s+ if you are not referring to it anymore in your tool or code.

edited Dec 13, 2018 at 18:49

answered Dec 13, 2018 at 18:37

The fourth bird

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Comments

Code Maniac · Accepted Answer · 2018-12-13 18:35:11Z

1

As per supplied data this will do job for you

[A-Za-z\s]+CONTACT:\s+\S+

Explanation

[A-Za-z\s]+ - Matches any alphabet or space one or more time.
CONTACT: - Matches CONTACT:.
\s+ - Matches one or more space character.
\S+ - Matches one or more non space character.

Demo

answered Dec 13, 2018 at 18:35

Code Maniac

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