正则表达式 C# - 中间的可选组

Question

I have such source text with an optional group in the middle:

GH22-O0-TFS-SFSD 00-1-006.19135
GH22-O0-TFS-SFSD 00-1-006.1.19135

Desired value in the first case will be '19135' and in the second '1.19135'.

Regex has to match the whole string and select all characters after first "." - which is my Group 1. I tried to make subgroups and mark Group 3 as optional but it is not working.

Regex:

.*\.0*(([0-9])(\.0*([0-9]+)))

How it should be changed to capture desired values?

Answer 1

You can use

^(.*?)\.0*(\d+)(?:\.0*(\d+))?$

See the regex demo . Details :

• ^ - start of string
• (.*?) - Group 1: any zero or more chars other than an LF char as few as possoble (as *? is a lazy quantifier)
• \\. - a dot
• 0* - zero or more zeros
• (\\d+) - Group 2: any one or more digits
• (?:\\.0*(\\d+))? - an optional occurrence of . , zero or more zeros, then Group 3 capturing one or more digits
• $ - end of string.

Answer 2

I hope I understand your goals and this should work:

.*?\.([\d.]+)

• .*?\\. - loosely capture everything leading up to the first period
• ([\\d.]+) - capture the remaining digits and periods into capture group #1

https://regex101.com/r/0t9Ijy/1

Answer 3

This should work for you:

.*?\.(.*)

This will match the whole string and include everything after the first period in capture group 1 regardless of character type.