need help splitting text

Hi everyone, I need to split text which contains random text with the dash ‘-’ character surrounded by whitespaces and also dash without whitespaces. I need to split it around the dash which is not surrounded by whitespace. I assume this can be done with a regex, but I can’t figure out the pattern.

Sample text: “this is a - sample test to demonstrate-what i wrote - above”
Desired split output: “this is a - sample test to demonstrate”, “what i wrote - above”

Any help is appreciated.

Hi John. You could use -split “\b-\b” to get the split you want.

Thank you Stein, that worked. Can you explain what exactly does it do? I found that \b means word boundary, but that doesn’t really help me understand the regex.

“Matches at a position that is followed by a word character but not preceded by a word character, or that is preceded by a word character but not followed by a word character.”

Keep in mind that “word characters” means letters, numbers and underscores (mostly; there’s a little bit of variance here between different regex implementations.) Relying on \b might cause you problems if the hyphen has some other non-whitespace character on either side, such as parentheses, punctuation marks, etc.

Here’s a tweak to the pattern which uses negative lookbehind and lookahead assertions to make sure that the hyphen does not have a whitespace character on either side of it:

$text = 'This - is - a-(test) - One - Two - Three'

Write-Verbose -Verbose 'Split with \b pattern'
$text -split '\b-\b'

Write-Verbose -Verbose 'Split with whitespace negative assertions pattern'
$text -split '(?<!\s)-(?!\s)'

Reference on lookahead / lookbehind assertions:

Thanks Dave, I guess I should spend some time on reg. expressions, I’ve been trying to avoid them until now :slight_smile:

You can also use positive “Lookaround” regexes with \S


Will match any - that is immediately preceeded and immediately followed by any non-whitespace character.