Regex to match {12} digit number & other pattern, multiline, when any characters can be between them

Question

I am trying to create a regex, but I am not sure at this point, if it is possible:

As my example: https://regex101.com/r/JRBYyw/6

Requirements:

• I need regex to match 12 numbers
• after or before 12 numbers there can be ANY characters in multiple - different amount of lines
• I want to match pattern [A-Z]{4}\s?\d{7} which can be after 12 digit number random-amount of times (between them again, random other characters in multiple lines)
• I want to match [A-Z]{4}\s?\d{7} so many times, until there is another 12 digit number somewhere in the text before it - not only directly before it, but between other text again.
• If it helps we can assume that 12 digit number and A-Z pattern will be on a new line, at the start of it.

Answer 1

You can use a two-pass approach: 1) extract all blocks of texts that start with 12-digit numbers and span up to the next 12-digit number or end of text, and 2) then extract the letter-digit patterns from each block.

Here is the first regex:

^(3\d{11})\R+([\s\S]*?)(?=\R3\d{11}|\z)

See the regex demo. The 12-digit numbers are in Group 1 here. Then, take Group 2 as input for

\d{12}|[a-zA-Z]{4}\s?\d{7}

that matches either 12 digits, or four letters, an optional whitespace and then seven digits.

See this regex demo