Is this possible to GREP?

[Victoria Bampton]

There's clearly lots of experience here... can anyone tell me if this is possible to do a find/replace GREP?

Links like those following are spread throughout a series of documents. I need to change the bit after the hash (e.g., #sub_InstallingLightroom) to remove the chunk before the underscore, put a hyphen before each uppercase character, and change the uppercase to lowercase (e.g., it becomes #installing-lightroom). That could be multiple finds/replacements, as I can deal with some of it, but I'm getting stuck on targeting and transforming those uppercase characters. Is it doable? Any bright ideas would be greatly appreciated!

<a href="/premium-classic/before-you-start.xhtml#sub_InstallingLightroom">Installing Lightroom</a>
<a href="/premium-classic/before-you-start.xhtml#box_MultipleComputers">Multiple Computers</a>
 <a href="/premium-classic/before-you-start.xhtml#sub_KeepingLightroomUpdated">Keeping Lightroom Updated</a>
<a href="/premium-classic/managing-your-photos.xhtml#sub_ManagingFoldersInLightroomAndOnTheHardDrive">Managing Folders in Lightroom and on the Hard Drive</a>

<a href="/premium-classic/managing-your-photos.xhtml#sub_ChangingTheFolderStructure">Changing the Folder Structure</a>

[MediaMouth]

The grep experts here are always impressive.  If they can't get it done with regex, a JS solution can.

On Jan 26, 2024, at 05:49, Victoria Bampton <vict...@victoriabampton.com> wrote:

There's clearly lots of experience here... can anyone tell me if this is possible to do a find/replace GREP?

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[jj]

Hi Victoria,

Here is a possible two pass solution:

First:

A Case sensitive Find / Replace :
   
    (?<=href=")([^#]+)#[^_]+_([A-Z][a-z]+)([A-Z][a-z]+)?([A-Z][a-z]+)?([A-Z][a-z]+)?([A-Z][a-z]+)?([A-Z][a-z]+)?([A-Z][a-z]+)?([A-Z][a-z]+)?([A-Z][a-z]+)?([A-Z][a-z]+)?(?=")
   
Replacement:
   
    \1#\L\2-\3-\4-\5-\6-\7-\8-\9-\10-\11
   
That will give you:

    <a href="/premium-classic/before-you-start.xhtml#installing-lightroom--------">Installing Lightroom</a>
    <a href="/premium-classic/before-you-start.xhtml#multiple-computers--------">Multiple Computers</a>
     <a href="/premium-classic/before-you-start.xhtml#keeping-lightroom-updated-------">Keeping Lightroom Updated</a>
    <a href="/premium-classic/managing-your-photos.xhtml#managing-folders-in-lightroom-and-on-the-hard-drive-">Managing Folders in Lightroom and on the Hard Drive</a>
    <a href="/premium-classic/managing-your-photos.xhtml#changing-the-folder-structure------">Changing the Folder Structure</a>    

Second:
   
Find / Replace:

    -+(?=">)
   
Let the replacement be empty:

That should work up to 10 terms camelCased query fragments.

HTH

Jean Jourdain

[Victoria Bampton]

Oh my goodness, you are amazing! That worked perfectly. That worked perfectly and has saved me days of work. Thank you so much!

[Neil Faiman]

There may be a way of doing this with a single operation. Usually, when approaching a problem like this, I just find a find-and-replace that will do the job if applied repeatedly some smallish number of times.

So, we’ll start out with a pattern that will leave the “hash-mark lowercase-string underscore” prefix intact as a marker, find the first subsequent uppercase letter in the fragment (if any), lowercase it, and insert the hyphen.

Find: (?i)(href="[a-zA-Z/-]+\.x?html#)(?-i)([a-z]+?_[-a-z]*)([A-Z])

Replace: \1\2-\l\3

Breaking this down:

• (?i) Means that the pattern is case-insensitive.
• (href="[a-zA-Z/-]+\.x?html) matches (and captures) the initial part of a link URL string (to make sure that we don’t inadvertently transform arbitrary text in the document).
• (?-i) switches the remainder of the pattern to case-sensitive.
• (#[a-z]+?_[-a-z]*) matches and captures
• A string of lowercase letters followed by an underscore
• A possibly empty string of lowercase letters and hyphens.
• ([A-Z]) matches and captures the first uppercase letter in the fragment.

The replacement string consists of everything up to the uppercase letter unchanged; a hyphen; and the uppercase letter, lower-cased. (“\l” means “lower-case the next character in the replacement string.)

If we apply this find-and replace to your example string

<a href="/premium-classic/before-you-start.xhtml#sub_KeepingLightroomUpdated">Keeping Lightroom Updated</a>

We will get

<a href="/premium-classic/before-you-start.xhtml#sub_-keepingLightroomUpdated">Keeping Lightroom Updated</a>

Applying it repeatedly, we get

<a href="/premium-classic/before-you-start.xhtml#sub_-keeping-lightroom-updated">Keeping Lightroom Updated</a>

So you want to apply this with a  find-and-replace-all to the entire document repeatedly until it doesn’t do anything any more. (Since it’s a no-op if it doesn’t match anything, you could just apply it five, or ten, or twenty times — whatever seems like a reasonably upper limit on the number of words in the fragment.)

Now we don’t need to marker any more, and we have an extra hyphen, so we will use a second pattern to clean that up:

Find: (?i)(href="[a-zA-Z/-]+\.x?html#)(?-i)[a-z]+?_-

Replace: \1

Do a find-and-replace-all, and this will remove the “lower-case-string underscore hyphen” from the start of each fragment:

 <a href="/premium-classic/before-you-start.xhtml#keeping-lightroom-updated">Keeping Lightroom Updated</a>

Regards,

Neil Faiman

[Benjamin Irwin]

There are a couple of other options for search and replace.  SED and AWK are designed specifically for that purpose.  The following is an example taken from "tldr"; a great resource for helpful linux documentation and examples. 

sed

Edit text in a scriptable manner. See also: awk, ed. More information: https://www.gnu.org/software/sed/manual/sed.html.

• Replace all apple (basic regex) occurrences with mango (basic regex) in all input lines and print the result to stdout:

{{command}} | sed 's/apple/mango/g'

• Replace all apple (extended regex) occurrences with APPLE (extended regex) in all input lines and print the result to stdout:

{{command}} | sed -E 's/(apple)/\U\1/g'

• Replace all apple (basic regex) occurrences with mango (basic regex) in a specific file and overwrite the original file in place:

sed -i 's/apple/mango/g' {{path/to/file}}

• Execute a specific script [f]ile and print the result to stdout:

{{command}} | sed -f {{path/to/script.sed}}

• Print just the first line to stdout:

{{command}} | sed -n '1p'

• [d]elete the first line of a file:

sed -i 1d {{/path/to/file}}

• [i]nsert a new line at the first line of a file:

sed -i '1i\your new line text\' {{/path/to/file}}

[Victoria Bampton]

Thank you very much, especially for the breakdown of what the different elements do. I've learned a few new tricks from this thread, so I'll be watching the group carefully in future. 

Victoria

[Kaveh Bazargan]

Hi Victoria

This is a great group indeed. I find regex101 very useful for playing around. I know BBEdit has a great regex playground too. In regex101 you can save a search with a unique URL and it'll always be there, e.g. for others to refer too. I put one of the examples above here. I have a lot of regex patterns that an external program uses and I just have a sheet with links to lots of regex101 pages. 

All the best.

Regards
Kaveh

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