Sorry for being late ! So, here are, below, some explanations about my regex S/R :

SEARCH (?-s)^.+#\x20?(\d+)\R(?=.+#\x20?\1)

REPLACE Leave EMPTY

• First, the (?-s) in-line modifier ensures that any further . regex symbol corresponds to a single standard character, only and not to a line-break char !

• So, the next part ^.+#\x20? searches, from beginning of line ( ^ ), any non-null range of characters ( .+ ), followed by the # symbol and an optional space char (\x20?)

• Then, it looks for a non-null range of digits ( \d+ ), followed by line-break character(s)

• So, the regex engine looks for an entire line ( digits after the # are stored as group 1 as embedded in parentheses ) but ONLY IF the next line ends with the same number !

• This condition can be expressed with a look-ahead structure (?=......) which are rather a user assertion in the same way that, for instance, the $ symbol is a system assertion, looking for the zero length assertion “end of line” !

• So current line must be followed with the regex .+#\x20?\1, which represents, again, a non-null range of standard characters followed with a # and possibly a space char and finally the group 1 ( \1 ) which is the ending number of the current line

• Note that the ^ assertion for the second line, in the look-ahead structure, is useless as the range (.+) comes next the line-break char(s) \R, anyway !

• As the replacement zone is empty, the current line, with its line-break, is just deleted

For a quick oversight about regular expressions, see the N++ documentation, below :

https://npp-user-manual.org/docs/searching/#regular-expressions

See also the main links regarding the Boost regex library, used by the regex N++ engine :

https://www.boost.org/doc/libs/1_70_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html

https://www.boost.org/doc/libs/1_70_0/libs/regex/doc/html/boost_regex/format/boost_format_syntax.html

Finally, see this FAQ topic about regular expressions :

https://community.notepad-plus-plus.org/topic/15765/faq-desk-where-to-find-regex-documentation

Best Regards,

guy038

Hi, @jim-erlich and All,

Many thanks for all your information ! It should be very easy to get the right solution !

The most important points are :

• Your file is already sorted by ascending #number

• And, in case of 1 duplicate line, it is located right after the original line !

---

Now, I don’t know how your preliminary sort behaved with numbers, separated with a space char from the # symbol ?

For instance :

Are lines sorted, as below ( case A ) :

The dog went to the park - #4599
The cat went to the park - # 4657
The kid went to the park - #4797
The lizard went to the zoo - # 5100
The cat went to the zoo - #5120

OR

Are lines sorted, like ( case B ) :

The cat went to the park - # 4657
The lizard went to the zoo - # 5100
The dog went to the park - #4599
The kid went to the park - #4797
The cat went to the zoo - #5120

Indeed, the N++ sort would place the line # 10000 before the line #5000, as space code-point is smaller than code-point of a digit !

---

Anyway, assuming a sort, like in case A and the initial text :

The dog went to the park - #4599
You went to the zoo - # 4640
He went to the park - # 4640
The cat went to the park - #4657
The kid went to the park - # 4657
The girl went to the park - #4900
The lizard went to the zoo - # 5100
The cat went to the zoo - #5100
I went to the park - #7500
We went to the zoo - #7500
They went to the park - #14000

Here is the road map :

• Open your file in N++

• Open the Replace dialog ( Ctrl + H )

• SEARCH (?-s)^.+#\x20?(\d+)\R(?=.+#\x20?\1)

• REPLACE Leave EMPTY

• Tick the Wrap around option

• Select the Regular expression search mode

• Click once on the Replace All button or several times on the Replace button

Voila !

You should get your expected list :

The dog went to the park - #4599
He went to the park - # 4640
The kid went to the park - # 4657
The girl went to the park - #4900
The cat went to the zoo - #5100
We went to the zoo - #7500
They went to the park - #14000

---

Note that if your sort is rather like in case B, it shouldn’t be be difficult to get, again, the case A order and run the regex S/R, afterwards ;-))

Next time, if everything was OK, I’ll explain how this regex S/R works !

Best Regards,

guy038

Flawless… absolutely amazing. You don’t understand how thankful I am for your detailed and correct response. This is a whole new language for me and I am amazed. thank you again.

Many thanks for all your information ! It should be very easy to get the right solution !

The most important points are :

• Your file is already sorted by ascending #number

• And, in case of 1 duplicate line, it is located right after the original line !

Now, I don’t know how your preliminary sort behaved with numbers, separated with a space char from the # symbol ?

For instance :

Are lines sorted, as below ( case A ) :

The dog went to the park - #4599
The cat went to the park - # 4657
The kid went to the park - #4797
The lizard went to the zoo - # 5100
The cat went to the zoo - #5120

OR

Are lines sorted, like ( case B ) :

The cat went to the park - # 4657
The lizard went to the zoo - # 5100
The dog went to the park - #4599
The kid went to the park - #4797
The cat went to the zoo - #5120

Indeed, the N++ sort would place the line # 10000 before the line #5000, as space code-point is smaller than code-point of a digit !

Anyway, assuming a sort, like in case A and the initial text :

The dog went to the park - #4599
You went to the zoo - # 4640
He went to the park - # 4640
The cat went to the park - #4657
The kid went to the park - # 4657
The girl went to the park - #4900
The lizard went to the zoo - # 5100
The cat went to the zoo - #5100
I went to the park - #7500
We went to the zoo - #7500
They went to the park - #14000

Here is the road map :

• Open your file in N++

• Open the Replace dialog ( Ctrl + H )

• SEARCH (?-s)^.+#\x20?(\d+)\R(?=.+#\x20?\1)

• REPLACE Leave EMPTY

• Tick the Wrap around option

• Select the Regular expression search mode

• Click once on the Replace All button or several times on the Replace button

Voila !

You should get your expected list :

The dog went to the park - #4599
He went to the park - # 4640
The kid went to the park - # 4657
The girl went to the park - #4900
The cat went to the zoo - #5100
We went to the zoo - #7500
They went to the park - #14000

Note that if your sort is rather like in case B, it shouldn’t be be difficult to get, again, the case A order and run the regex S/R, afterwards ;-))

Next time, if everything was OK, I’ll explain how this regex S/R works !

Best Regards,

guy038

Hello, @jim-erlich,

Before finding a way to solve your problem, we need additional information :

• In your previous post, which is deleted by now, you spoke about a giant file : what is the approximative size and how many lines contains this file ?

• Do you mind if your file is modified by a preliminary sort ? If you don’t mind, this could, significantly simplify all the process ! )

• How many digits can exist after the # symbol ? Is 5 the maximum or 8 or 10 digits or … ?

• What is the maximum of lines between two “duplicate” lines ( for instance xxxxxxxx#2345 and yyyyyyyy#12345 )

• Are they more than 2 'duplicate" lines ( I mean, for instance, 6 lines ending with #12345 )

• In case of multiple “duplicate” lines, which one you want to keep : the first duplicate line or the last duplicate ?

Note that we can cope with a possible space character between the # symbol and the number Not a problem !

See you later !

Best regards,

guy038

• 12,000 lines broken up into different pages. Each page can have 300 to 1,100 lines.
• Right now the lines are in Ascending order based upon the number.

For example:
The dog went to the park - #4599
The cat went to the park - #4657
The kid went to the park - #4797
The lizard went to the zoo - #5100
The cat went to the zoo - #5120
etc…

Ideally, I would like to keep the numbers in Ascending order like this, and locate the lines that have duplicate numbers

• The number of digits after the # symbol is 1 to 5… the highest number being about 14000
• Oh this is good… the duplicate line that has the duplicate number SHOULD BE on the next line. So it will be like this

For example:
The dog went to the park - #12554
The cat went to the park - #12554

^^^ The formula should say “Hey!! These two numbers are identical” and then I will delete one of them manually.

• There will be only 2 ‘duplicate’ lines. There will not be 6 lines ending with #12345
• Keep the last duplicate line, delete the first

I hope this is clear, let me know if there is anything else.

Thank you

Before finding a way to solve your problem, we need additional information :

• In your previous post, which is deleted by now, you spoke about a giant file : what is the approximative size and how many lines contains this file ?

• Do you mind if your file is modified by a preliminary sort ? If you don’t mind, this could, significantly simplify all the process ! )

• How many digits can exist after the # symbol ? Is 5 the maximum or 8 or 10 digits or … ?

• What is the maximum of lines between two “duplicate” lines ( for instance xxxxxxxx#2345 and yyyyyyyy#12345 )

• Are they more than 2 'duplicate" lines ( I mean, for instance, 6 lines ending with #12345 )

• In case of multiple “duplicate” lines, which one you want to keep : the first duplicate line or the last duplicate ?

Note that we can cope with a possible space character between the # symbol and the number Not a problem !

See you later !

Best regards,

guy038