PowerShell Regular Expression match Y or Z

Question

I am trying to match some strings using a regular expression in PowerShell but due to the differing format of the original string that I'm extracting from, encountering difficulty. I admittedly am not very strong with creating regular expressions.

I need to extract the numbers from each of these strings. These can vary in length but in both cases will be preceded by Foo

PC1-FOO1234567
PC2-FOO1234567/FOO98765

This works for the second example:

'PC2-FOO1234567/FOO98765' -match 'FOO(.*?)\/FOO(.*?)\z'

It lets me access the matched strings using $matches[1] and $matches[2] which is great.

It obviously doesn't work for the first example. I suspect I need some way to match on either / or the end of the string but I'm not sure how to do this and end up with my desired match.

Suggestions?

Answer 1

You may use

'FOO(.*?)(?:/FOO(.*))?$'

It will match FOO, then capture any 0 or more chars as few as possible into Group 1 and then will attempt to optionally match a sequence of patterns: /FOO, any 0 or more chars as many as possible captured into Group 2 and then the end of string position should follow.

See the regex demo

Details

• FOO - literal substring
• (.*?) - Group 1: any zero or more chars other than newline, as few as possible
• (?:/FOO(.*))? - an optional non-capturing group matching 1 or 0 repetitions of:
  • /FOO - a literal substring
  • (.*) - Group 2: any 0+ chars other than newline as many as possible (* is greedy)
• $ - end of string.