Match a not 8 character (digit/a-z/A-Z) long word through regex

Question

This is the first question I post so sorry for anything I might screw up.

I've spent the past hour experimenting and searching for a way to replace "not 8 character (digit/a-z/A-Z) long word" with blank space (or in other words delete anything but those words) in Notepad++ through regular expressions.

I managed to bookmark the lines containing them but I'm stuck with the whole line that has that word, I just want those specific words. I'd appreciate any help, thanks a lot!

Edit2: A better way to phrase this is:
To remove anything that isn't: 8 character long that starts with an S and only contains digits and letters. In other words, remove anything that isn't S******* where *=digit,letter

Edit: I realized that's not enough to understand the situation so here's an example. I want to process this:

Here's your first code: S284JF2B
Here's your second code: SKE093JF
Here's your third code: S28fka30

And get this output:

S284JF2B
SD34EQ5M 
SASFKA30

The actual file has lots of other characters that are not just digits/letters and the codes I want on the output are always 8 character long (digits/Uppercase letters) always starting with an S.

Answer 1

I'd use the following regex ^.*(S[A-Z0-9]{7})(?!=[A-Z0-9]).*$:

• Ctrl+H
• Find what: ^.*(S[A-Z0-9]{7})(?!=[A-Z0-9]).*$
• Replace with: $1
• DO NOT check . matches newline
• Replace all

Explanation:

^               : begining of line
  .*            : any character 0 or more times
  (             : start group 1
    S[A-Z0-9]{7}: S followed by 7 alphanumeric characters
  )             : end group
  (?!=[A-Z0-9]) : negative lookahead to make sure there are no alphanum after
  .*            : any character 0 or more times
$               : end of line

Answer 2

I have tried with following text to match your problem with the additional non-alphanumeric characters.

<protocol="toto" john="doe" Here's your first code: S284JF2B sign="+" />
<protocol="toto" john="doe" Here's your second code: SKE093JF sign="+" />
<protocol="toto" john="doe" 8char="s2345678" Here's your third code: S28fka30 sign="+" />

I used the following regular expression

\b(\w{1,7}|(?=[^S])\w{8}|S(?![A-Za-z0-9]{8})\w{8}|\w{9,})\b|[^\w\r\n]

I obtained only the codes when replacing with nothing and selected the option "Match case" in the replacement windows.

With a live demo here: https://regex101.com/r/wW3eB1

Explanations:

• \b(...)\b: word between boundaries
• \w{1,7}: word of 1 to 7 letters
• (?=[^S])\w{8}: word of 8 letters not starting by 'S'
• S(?![A-Za-z0-9]{8})\w{8}: word starting with a 'S', with 8 characters but containing something other than alpha-numeric (i.e. an underscore)
• |\w{9,}: word of 9 letters or more
• [^\w\r\n]: character that is neither a word or an EOL character

Answer 3

I have two possible solutions. Both solutions require the string to be 8 characters long and begin with an S.

Given the this sample text:

the problem is it's not the words that do not contain any words that I don't want 
but actually any string that isn't a string that starts with an S and is 8 character long. 
Example: S294KS12 this is the type of string I want on the document. Contains 8 characters 
that are either digits or letters and starts with an S

SOMETIME
S294KS12
S1234567
S123456A

Option 1

This solution only finds strings which are 8 characters long and start with an S.

\bS[A-Z0-9]{7}\b

Live Demo

https://regex101.com/r/lK0aO9/1

Matches from Sample

S294KS12
SOMETIME
S294KS12
S1234567
S123456A

Explanation

NODE                     EXPLANATION
----------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
----------------------------------------------------------------------
  S                        'S'
----------------------------------------------------------------------
  [A-Z0-9]{7}              any character of: 'A' to 'Z', '0' to '9'
                           (7 times)
----------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
----------------------------------------------------------------------

Options 2

This solution does additional checking to ensure there is at least one additional letter and one number.

\bS(?=[A-Z]*[0-9])(?=[0-9]*[A-Z])[A-Z0-9]{7}\b

Live Demo

https://regex101.com/r/vH4lX2/3

Matches from Sample

S294KS12
S294KS12
S123456A

Explanation

NODE                     EXPLANATION
----------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
----------------------------------------------------------------------
  S                        'S'
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    [A-Z]*                   any character of: 'A' to 'Z' (0 or more
                             times (matching the most amount
                             possible))
----------------------------------------------------------------------
    [0-9]                    any character of: '0' to '9'
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    [0-9]*                   any character of: '0' to '9' (0 or more
                             times (matching the most amount
                             possible))
----------------------------------------------------------------------
    [A-Z]                    any character of: 'A' to 'Z'
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  [A-Z0-9]{7}              any character of: 'A' to 'Z', '0' to '9'
                           (7 times)
----------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
----------------------------------------------------------------------

Putting all together

To replace everything else, then I'd incoprporate the regular expression into ( ... )\s?|. Which will match everything, including the desired strings.

If you then use $1 in the Replace with option in Notepad++, then you'll be left with just your desired strings.

I recommend using option 2 above, and inserting that into the expression so it looks like this:

(\bS(?=[A-Z]*[0-9])(?=[0-9]*[A-Z])[A-Z0-9]{7}\b)\s?|.

Replace with: $1

Live Demo

https://regex101.com/r/gO7zV7/1

Answer 4

To match everything but the tokens from your example:

(^|\s)(?!S\w{7}\b)\S*

For a live demo, see https://regex101.com/r/rW8mF0/4

To match any non-8 character word:

\b\w{1,7}\b|\b\w{9,}\b

It matches words of length 1 - 7 OR words of length 9 and more.

For a live demo, see https://regex101.com/r/fX2sE5/1

Answer 5

Description

Lacking any proper examples, this will find substrings that are 8 characters long and not containing any letters. The substring must be bracketed by either whitespace or at the beginning or end of the string

(?<=\s|^)[^a-zA-Z0-9\s]{8}(?=\s|$)

Example

Live Demo

https://regex101.com/r/gS9uN7/1

Sample text

I've spent the past hour experimenting and searching for a way to replace "not 8 character (digit/a-z/A-Z) $#@!#$>< fd long word" with blank space (or in other words delete anything but those words) in Notepad++ through regular expressions.

Sample Matches

$#@!#$><

After Replacement

I've spent the past hour experimenting and searching for a way to replace "not 8 character (digit/a-z/A-Z) fd long word" with blank space (or in other words delete anything but those words) in Notepad++ through regular expressions.

Explanation

NODE                     EXPLANATION
----------------------------------------------------------------------
  (?<=                     look behind to see if there is:
----------------------------------------------------------------------
    \s                       whitespace (\n, \r, \t, \f, and " ")
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    ^                        after an optional start of the string
----------------------------------------------------------------------
  )                        end of look-behind
----------------------------------------------------------------------
  [^a-zA-Z0-9\s]{8}           any character except: 'a' to 'z', 'A' to
                           'Z', '0' to '9', whitespace (\n, \r, \t, \f, and " ")
                           (8 times)
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    \s                       whitespace (\n, \r, \t, \f, and " ")
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    $                        before an optional \n, and the end of a
                             "line"
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------