I am trying to get only the "nonpersonalizedusername" including its number or the surname. To add more detail, I'd like to accomplish something like: If there's an @-Symbol, get me everything that is in front of that @-Symbol, otherwise get me the whole string. Plus, if then there's a dot "." in it, get me everything after that dot.

Let's assume I have the following stringsof userPrincipalNames and/or displayNames:

nonpersonalizedusername004
nonpersonalizedusername019@domaina.local
prefixc.nonpersonalizedusername044@domaina.local
nonpersonalizedusername038@domainb.local
prefixa.nonpersonalizedusername002@domaina.local
prefixb.nonpersonalizedusername038@domainb.local
givenname.surname
givenname.surname@domaina.local

What I got so far is this expression:

^(?:.*?\.)?(. ?)(?:@.*)?$

but this only works, if there's an @-Symbol AND that "prefixing"-Dot in the string OR neither Dot nor @-Symbol. If there's an @-Symbol, but no prefixing-dot, I'm getting only that "local"-part from the end.

https://regex101.com/r/1aflGH/1

CodePudding user response：

You can use

^(?:[^@.]*\.)?([^@] )(?:@.*)?$

See the regex demo. The \n is added to the negated character classes at regex101 as the test is run against a single multiline string.

Details:

• ^ - start of string
• (?:[^@.]*\.)? - an optional sequence of any zero or more chars other than @ and . and then a .
• ([^@] ) - Group 1: one or more chars other than @ char
• (?:@.*)? - an optional sequence of @ and then the rest of the line
• $ - end of string.

CodePudding user response：

You might optionally repeat matches until the last dot before the @, and then capture the rest after that do till the @ in group 1.

^(?:[^@.]*\.)*([^@.] )

The pattern matches:

• ^ Start of string
• (?: Non capture group
  • [^@.]*\. Optionally repeat matching any char except @ or ., then match .
• )* Close non capture group and optionally repeat
• ( Capture group 1
  • [^@.]
• ) Close group 1

Regex demo

Powershell example

$s = @"
nonpersonalizedusername004
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
givenname.surname
[email protected]
"@

Select-String '(?m)^(?:[^@.\n]*\.)*([^@.\n] )'  -input $s -AllMatches | Foreach-Object {$_.Matches} | Foreach-Object {$_.Groups[1].Value}

Output

nonpersonalizedusername004
nonpersonalizedusername019
nonpersonalizedusername044
nonpersonalizedusername038
nonpersonalizedusername002
nonpersonalizedusername038
surname
surname