Regex code to match string start and end position, but exclude specific matches-CodePudding

Can someone help, please! I have a list of account numbers, below is an example of the formats. Essentially all accounts start with "DO", they then have four numbers, they then have a sibling account with an "M" on the end and another with a "PY". DO1200, DO1200M, DO1200PY

I want to identify all accounts that end in "M" and have the following code to do that.

^DO.\[M\]$

I have 3 accounts I want to exclude from this list, DO1210M, DO1215M & DO1220M and I haven't been able to find an answer.

I've tried searching StackOverflow for other answers such as:

^/(?!DO1210M|DO1215M|DO1220M)(\[a-z0-9\] )$

And trying to add this into my code, and while some of my attempts still retrieve results they never actually exclude the accounts I'm trying to exclude.

CodePudding user response：

You can use a negative lookahead with a non capturing group:

^(?!(?:DO1210M|DO1215M|DO1270M)$)^DO\d{4}M$
^                                ^              #beginning of the line
                               $          $     #end of line
 (?!                            )               #negative lookahead
    (?:                       )                 #non capturing group
              |       |                         #logical OR
       XXXXXXX XXXXXXX XXXXXXX                  #text not to match
                                  DO     M      #Literal text
                                    \d          #any digit
                                      {4}       #quantifier, exactly 4 times

Example