正则表达式匹配不同情况下字符之前或之后的内容

Question

I have some troubles writing a regex

What I want to achieve, I want to match the following string 6.62 X 25.250755 L but only what is after the X character or there may be cases when I have to match the following string 25.250755 X 6.62 in this case I need to match what's before the X character and the final case is when I have something like this: 25.250755 LX 6.62 or 25.250755LX 6.62 (with or without space, with or without the L character)

This is what I have so far, but is not enough and I don't know how to continue form here on

/[Xx]([\s\S]*)$/gm

Answer 1

([0-9]*[.])?[0-9]+ ?L? X ([0-9]*[.])?[0-9]+ ?L? should work.

Answer 2

For your example data, you can repeat a group with a capture group to capture the value of the last iteration.

(?: ?\b(\d+(?:\.\d+)) ?[XL])+\b

• (?: Non capture group
  • ?\\b Match an optional space and a word boundary
  • ( Capture group 1
    • \\d+(?:\\.\\d+) Match 1 or more digits with an optional decimal part
  • ) Close group 1
  • ?[XL] Match an optional space and either X or L
• )+ Close the non capture group and repeat it 1 or more times
• \\b A word boundary

Regex demo