Bookmark lines that start with a year and month

I have a list like following:

20110512192714
20794709157481
20121203175303
20794709157481
20210131201708
20211101050154
20220501022609
79776361952441

Now I want to select lines that start with a year and month from left side in notepad++ by regex.
Note that years must start from 2000 to 2023.
I tried following regex:

20(?:0[0-9]|1[0-9]|20)[0-1][0-9]

above regex working good but have two problem:

1. Can’t select whole line of targets and select piece of target line.
   (sometimes maybe length of numbers are not same)

2. It can’t select
   some lines like following lines:

   20211101050154
   20220501022609

where is my regex problem?

>Solution :

Your pattern 20(?:0[0-9]|1[0-9]|20)[0-1][0-9] matches:

20 followed by a range 00-09 or range 10-19 or 20 followed by either 00-19 or 01-19

If yo want to match a line that starts with 2000 – 2023 and should only contain digits:

^20(?:2[0-3]|[01]\d)\d*$

If you want to include matching a month from 1 – 12 with an optional leading zero:

^20(?:2[0-3]|[01]\d)(?:0?[1-9]|1[012])\d*$

The year pattern matches:

• ^ Start of string
• 20 Match literally
• (?: Non capture group for the alternatives
  • 2[0-3] Match 20, 21, 22, 23
  • | Or
  • [01]\d Match from 00 to 19
• ) Close the non capture group
• \d* Match optional digits
• $ End of string

See a regex demo.

If you want to match the rest of the line that could contain any character, you can change the last part of the pattern from \d*$ to .*