具有多种模式的选择字符串，一行输出

Question

I am extracting info from a large text file. When I do this using the code below all my patterns go to separate lines. I would like them to output to one.

get-content c:\dev\test\data.txt | Select-String "First:","Last:" | Add-Content c:\dev\test\output.txt

This currently gives me:

John
Doe
Mary
Smith

I would like:

John Doe
Mary Smith

Answer 1

You could try something like this:

$text = @"
First: John
Last: Doe
lasld

First: Mary
dasd
Last: Smith
"@

$text | Select-String '(?s)First:\s+(\w+).*?Last:\s+(\w+)' -AllMatches |
ForEach-Object { $_.Matches } |
ForEach-Object { "$($_.Groups[1].Value) $($_.Groups[2].Value)" }

Output:

John Doe
Mary Smith

It requires the input as a single multi-line string, so you would need to use $text = Get-Content "c:\\dev\\test\\data.txt" -Raw or $text = (Get-Content "c:\\dev\\test\\data.txt") -join [environment]::NewLine

Regex101: https://regex101.com/r/bD2oU3/1

Update: I realized that some people may have middlenames, so as long as the line ends with the name like the samples, you could use the regex below to include more than the first word after "First:" and "Last:". It also removes trailing whitespace on the line

$text = @"
First: John Lala     
Last: Doe
lasld

First: Mary
dasd
Last: Smith Test
"@

$text | Select-String '(?ms)First:\s+(.*?)\s{0,}$.*?Last:\s+(.*?)\s{0,}$' -AllMatches |
ForEach-Object { $_.Matches } |
ForEach-Object { "$($_.Groups[1].Value) $($_.Groups[2].Value)" }

John Lala Doe
Mary Smith Test