how to remove empty spaces from a particular tag (regular expression)
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good day, I made this regular expression to remove empty spaces from a particular tag that has many empty spaces and tabs:
(?-s)(\G(?!^)|<p\s+class="oyric">)((?!</p>).)*?\K\s\s+but it does not work well<p class="oyric"> Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped. </p>Output should be:
<p class="oyric">Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped.</p>
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Hi, @Robin-cruise and All,
You were not very far from the right solution ! The way to replace something :
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In a particular tag section, as
<p>........</p> -
In a particular tag section, with a particular class name, as
<p class="test">Bla bla blah</p>
has already been discussed in these posts :
So, the general regex solution, when you want to perform a Search/Replacement, ONLY in an area, which is located between two particular boundaries, is :
SEARCH
(?-s)(\G|BR)((?!ER).)*?\KSR OR(?s)(\G|BR)((?!ER).)*?\KSRREPLACE RR
where :
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BR ( Begining Regex ) is the regex which defines the start of the defined zone, for the search/replacement
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ER ( Ending Regex ) is the regex which defines the end of the defined zone, for the search/replacement
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SR ( Search Regex ) is the regex which defines the expression to search, in any defined zone
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RR ( Replace Regex ) is the regex which defines the expression replacing the Search Regex, in any defined zone
In your case :
BR =
<p class="oyric">ER =
</p>SR =
((?<=>)\h+|\h+(?=<|\h))RR =
NothingNotes :
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SR is a search of any of the two alternatives, separated with the
|symbol, and surrounded by parentheses, because of the lowest priority of the alternation symbol|-
(?<=>)\h+which tries to match any non-null range of horizontal blank chars ( spaces or tabulations ), if preceded with the>symbol -
\h+(?=<|\h))which tries to match any non-null range of horizontal blank chars ( spaces or tabulations ), if followed by, either, the<symbol or a final horizontal blank character
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As all these blank characters matched have to be deleted, the replacement zone is just empty
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First, the regex tries to find the string
<p class="oyric">, followed by the shortest range, even null, of characters,.*?, till the search regex, explained above, with the condition that the string</p>must not located at any position of this range -
Due to the
\Ksyntax, the regex engine resets its working location and forgets any previous match. So the final match is ,simply, the part described above((?<=>)\h+|\h+(?=<|\h))( SR ) -
After this first match, it can only match the zero-length assertion
\G, followed, again, with a possible other shortest range, even null … … … as just above ! -
When the regex engine skips the ending boundary
</p>, the\Gcannot be verified anymore and the only way to match something else is to grab, again, a<p class="oyric">string, further on ! -
If you are only interested in single-line ranges
BR.........ER, use the(?-s)modifier, at beginning of the search regex -
If you may have some multi-lines ranges
BR.........ER, use the(?s)modifier, at beginning of the search regex
So, Robin, let’s imagine the sample text, below :
<p class="oyric"> Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped. </p> <p class="Tag_1"> Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped. </p> <p class="oyric"> Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped.</p> <p class="Tag_2">bla blah blah </p> <p class="oyric"> This is a test </p> <p class="Tag_3">bla blah blah </p> <p class="oyric"> The final test </p> <p class="oyric"> Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped. </p> <p class="Tag_2">bla blah ....blah </p> <p class="oyric"> This is an other test to verify if the regex is correct </p>Using the following regex S/R :
SEARCH
(?s)(\G|<p class="oyric">)((?!</p>).)*?\K((?<=>)\h+|\h+(?=<|\h))REPLACE
Leave EMPTYYou should get the expected text, below :
<p class="oyric">Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped.</p> <p class="Tag_1"> Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped. </p> <p class="oyric">Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped.</p> <p class="Tag_2">bla blah blah </p> <p class="oyric">This is a test</p> <p class="Tag_3">bla blah blah </p> <p class="oyric">The final test</p> <p class="oyric">Laurie Strode comes to her final confrontation with Michael Myers, the masked figure who has haunted her since she narrowly escaped.</p> <p class="Tag_2">bla blah ....blah </p> <p class="oyric">This is an other test to verify if the regex is correct</p>Notes :
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It’s easy to verify that blank characters have been removed, ONLY in all areas
<p class="oyric">..........</p>, whatever they were single-line areas or a multi-lines blocks -
However, note that if a line ends with blank chars and the next line begins, also, with blank characters, this regex S/R will keep one blank char, either, at the end of this line and at the beginning of the next line !
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Finally, beware that, if words are separated with a mix of space and tabulation characters, only the final blank character will be kept !
For instance from text :
<p class="oyric"> Test #1 </p> ( Last BLANK char = SPACE ,before #1 ) <p class="oyric"> Test #2 </p> ( Last BLANK char = TABULATION, before #2 )You’ll obtain :
<p class="oyric">Test #1</p> ( SPACE char between Test and #1 ) <p class="oyric">Test #2</p> ( TABULATION char between Test and #2 )Best Regards,
guy038
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GREAT ! thank you very much ;)
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SEARCH
(?s)(\G|<p class="oyric">)((?!</p>).)*?\K((?<=>)\h+|\h+(?=<|\h))REPLACE
Leave EMPTY
by the way, there is a little problem in your regex, guy038. Now I discover that.
Seems that your regex selects all spaces outside the specified tag, and disturb
all my other lines.See a print screen:
or check regex on this code on notepad: https://regex101.com/r/dDBYSk/1
See what happen after “Replace all”. You will see that all tags with spaces before and after are modify, not only that particular tag I want. (<p class=“oyric”>)
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i’m thinking about swiss file knife plugins to build.
http://stahlworks.com/dev/swiss-file-knife.html
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Hello, @Robin-cruise and All,
Ah Yes ! My regex wasn’t enough accurate ! And worse, my formulation of the general regex solution was not exact too :-((
So, the general regex solution, when you want to perform a Search/Replacement in a specific area, only, is :
SEARCH
(?-s)(\G|BR)((?!ER).)*?\KSR OR(?s)(\G|BR)((?!ER).)*?\KSRREPLACE RR
where :
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BR ( Begining Regex ) is the regex which defines, either, the start of that specific area and the start for a possible Search Regex match
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ER ( Excluded Regex ) is the regex which defines the characters and/or strings
forbidden, from the Begining Regex position until a next Search Regex match. It, implicitly, defines a zone, where the Search Regex may occur -
SR ( Search Regex ) is the regex which defines the expression to search, if , both, the Begining Regex and the Excluded Regex are TRUE
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RR ( Replace Regex ) is the regex which defines the expression replacing the Search Regex
In your case, we must look for unnecessary blank characters, in a
<..........>area, without any<nor>inside. Hence, the excluded chars are , simply, the two symbols<and>Now, inside that area, possibly multi-lines, we’ll look for either:
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Case A : All blank characters,at beginning of lines, in case of a correct area, split in several lines
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Case B : All blank characters,at end of lines, in case of a correct area, split in several lines
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Case C : All blank characters, right after the
<symbol -
Case D : All blank characters, right before the
</p>ending tag -
Case E : All ranges of, at least, two blank characters, not followed from, either, a blank char or a
<symbol
Theses
5cases correspond to the different alternatives of the SR search regex, *separated with the|symbolSo, we have :
BR =
<p class="oyric">ER =
<|>SR =
(?:(^\h+)|\h+$|(?<=>)\h+|\h+(?=</p>)|(\h{2,})(?=[^<\h]))RR =
(?1$0)(?2\x20)Remarks :
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The assertion
\Gis considered as true ( current position of caret), during the first run of the regex. So, if you move the cursor inside the leading spaces of a line, in purpose, before running the reges S/R, it could wrongly match the remaining leading spaces, located after the cursor position -
So, in order to avoid theses matches, I added, for case E, the restrictive condition
(\h{2,})(?=[^<\h]), which must be true, after the blank matched range ! -
Regarding the replacement :
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If case A occurs, we must keep the leading spaces, stored in group
1So , we rewrite the entire match(?1$0) -
If cases B, C or D occurs, we need to delete all these blank chars =>
Nothingis rewritten -
If case E occurs, we just replace all the blank chars matched, stored in group
2with a single space character =>(?2\x20)
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Finally, we get this new regex S/R :
SEARCH
(?s)(?:\G|<p class="oyric">)(?:(?!<|>).)*?\K(?:(^\h+)|\h+$|(?<=>)\h+|\h+(?=</p>)|(\h{2,})(?=[^<\h]))REPLACE
(?1$0)(?2\x20)which should avoid the side-effects of my first attempt ;-))
Beware
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If you decide, before performing this regex S/R, to move the cursor, on purpose, inside the
<.........>area of a<p>tag, with a class different fromoyric, it will, also, match all the additional blank characters of that<.........>zone. Can’t do anything about this ! -
Luckily, once the caret is located after that first zone
<.........>, the behavior of the regex is, again, as expected :-))
Cheers,
guy038
PS :
I say, above, regarding the ER ( Excluded Regex ), that it, implicitly, defines a zone, where the Search Regex may occur
Just an example to explain this notion. Let’s consider these
3simple regexes :-
[^<>]+(?=\h), which searches the greatest range of chars, different of<and>, if followed with a blank char -
[^<]+(?=\h), which searches the greatest range of chars, different of<, if followed with a blank char -
[^>]+(?=\h), which searches the greatest range of chars, different of>, if followed with a blank char
Here is, below, the results, with any range of chars, underlined with
-and the blank char, underlined with^REGEX [^<>]+(?=\h) <p class="oyric">This is a test </p> <p class="Tag_3">bla blahh </p> <p class="oyric"> a test</p> - ------------------------^ --^ -^ -------------^ -^ -^ ------^ REGEX [^<]+(?=\h) <p class="oyric">This is a test </p> <p class="Tag_3">bla blahh </p> <p class="oyric"> a test</p> ----------------------------------------^ -----^ -----------------------------^ ----^ ----------------------^ REGEX [^>]+(?=\h) <p class="oyric">This is a test </p> <p class="Tag_3">bla blahh </p> <p class="oyric"> a test</p> --^ ------------------------^ -----^ -------------^ ----^ ------^As we use the greedy quantifier
+, it easy to visualize the complete zones where it is allowed to look for a blank character, underlined with^, in each case ;-))
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well done, thank you very much
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@guy038 said:
(?1$0)(?2\x20)
also, it can be replace with:
(?{2}$1 )such as:SEARCH:
(?:(^\h+)|\h+$|(?<=>)\h+|\h+(?=</p>)|(\h{2,})(?=[^<\h]))REPLACE BY:
(?{2}$1 )
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@guy038 I just review this post, because I like it and remembered the same thing from the post today.
SEARCH
(?s)(?:\G|<p class="oyric">)(?:(?!<|>).)*?\K(?:(^\h+)|\h+$|(?<=>)\h+|\h+(?=</p>)|(\h{2,})(?=[^<\h]))REPLACE
(?1$0)(?2\x20)What if, in case I have another tag, like
<em>So, @Robin Cruise scenario become:
<p class="oyric"> Laurie Strode comes to her final confrontation <em> with Michael Myers, the masked figure who has haunted her </em>since she narrowly escaped. </p>So, In this case, your regex does not remove empty spaces because of those
<em>
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This post is deleted!
