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    How to find two or more non-consecutive tabs in a line?

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    • glossar
      glossar last edited by

      I can confirm that it finds a line that contains two tabs but if a line doesn’t meet the criteria, it looks further (greedy, you say? :) )and hence finds the following line together, which in the end looks like “every other line”. But I’m pretty sure it skips the \r\n.of a line if this line contains only one tab. Can you limit the regex, so it should look for and within only one line (by line, I mean anything between ^ and \r\n).

      Alan Kilborn Meta Chuh 2 Replies Last reply Reply Quote 3
      • Alan Kilborn
        Alan Kilborn @glossar last edited by Alan Kilborn

        @glossar

        Ah, yes, okay, that makes sense. The [^\t]+ will capture across line-boundaries. At this point I will bow out and let the regex master @guy038 step in… :)

        And maybe he can comment on my “interesting disussion” post above as well.

        1 Reply Last reply Reply Quote 2
        • Meta Chuh
          Meta Chuh @glossar last edited by Meta Chuh

          maybe a screenshot helps:
          Imgur

          1 Reply Last reply Reply Quote 2
          • glossar
            glossar last edited by

            I can’t see the screenshots above - neither on this page nor when clicking on it. All I see is a broken-image-file-icon and “Imgur” next to it.

            1 Reply Last reply Reply Quote 0
            • Alan Kilborn
              Alan Kilborn last edited by

              Okay, one more try. It could be as simple(!) as changing it to this:

              (?-s)^.*?\t(?!\t).+?\t.*?$

              :)

              1 Reply Last reply Reply Quote 4
              • glossar
                glossar last edited by

                Thanks, that now works like a charm! :)

                While we are at it, how about building another regex that locates a line that contains no tab? :)

                Alan Kilborn 1 Reply Last reply Reply Quote 0
                • Alan Kilborn
                  Alan Kilborn @glossar last edited by

                  @glossar said:

                  regex that locates a line that contains no tab?

                  There might be better ones, but this one seems to work:

                  ^((?!\t).)*$

                  glossar 1 Reply Last reply Reply Quote 3
                  • guy038
                    guy038 last edited by guy038

                    Hi, @glossar, @alan-kilborn, and All,

                    A second solution could be :

                    SEARCH (?-s)(?=.*\t.*\t).+

                    A third solution could be, using the Mark dialog, w/o checking the Bookmark line option :

                    MARK (?-s)\t.*\t


                    Note, @alan-kilborn, that your regex should be changed into :

                    SEARCH (?-s)^.*?\t[^\t\r\n]+\t.*?$

                    To avoid wrong multi-lines match. However, this solution still misses some possibilities !


                    You may test these 3 regexes, above, against the sample test, below :

                    ---------------------------- 1 TEXT block without TAB -----> KO <----- ( because NO tabulation )
                    abcd
                    ---------------------------- 1 TAB  without TEXT ----------> KO <----- ( because ONE tabulation ONLY )
                    	
                    ---------------------------- 2 TABs without TEXT ----------- OK ------
                    		
                    ---------------------------- 3 TABs without TEXT ----------- OK ------
                    			
                    ---------------------------- 1 TAB  + 1 TEXT block --------> KO <----- ( because ONE tabulation ONLY )
                    abcd	
                    	abcd
                    ---------------------------- 1 TAB  + 2 TEXT blocks -------> KO <----- ( because ONE tabulation ONLY )
                    abcd	efgh
                    ---------------------------- 2 TABs + 1 TEXT block --------- OK ------
                    efgh		
                    	efgh	
                    		efgh
                    ---------------------------- 2 TABs + 2 TEXT blocks -------- OK ------
                    abcd	efgh	
                    abcd		ijkm
                    	efgh	ijkl
                    ---------------------------- 2 TABs + 3 TEXT blocks -------- OK ------
                    abcd	efgh	ijkl
                    ---------------------------- 3 TABs + 1 Text block --------- OK ------
                    abcd			
                    	efgh		
                    		ijkl	
                    			mnop
                    ---------------------------- 3 TABs + 2 Text blocks -------- OK ------
                    abcd	efgh		
                    abcd		ijkl	
                    abcd			monp
                    	efgh	ijkl	
                    	efgh		monp
                    		ijkl	monp
                    ---------------------------- 3 TABs + 3 Text blocks -------- OK ------
                    abcd	efgh	ijkm	
                    	efgh	ijkl	mnop
                    ---------------------------- 3 TABs + 4 Text blocks -------- OK ------
                    abcd	efgh	ijkl	mnop
                    ----------------------------------------------------------------------
                    

                    Best Regards,

                    guy038

                    1 Reply Last reply Reply Quote 3
                    • PeterJones
                      PeterJones last edited by PeterJones

                      @glossar , @Alan-Kilborn , @Meta-Chuh , et alia,

                      Unfortunately, the (?-s) only changes the behavior of . with respect to newlines; it doesn’t change character classes, so [^\t]+ means “one or more characters that don’t match a TAB, even if those characters are newlines”. By changing the full regex to (?-s)^.*?\t[^\t\r\n]+\t.*?$, I was able to get it to skip lines like @Meta-Chuh 's example of x instead of the TAB. The class [^\t\r\n] means “match one or more characters that isn’t any of TAB, CR (carriage return), or LF (line-feed)”

                      I am not as regex expert as @guy038, so I may be misinterpreting; however, the boost docs say (emphasis mine)

                      Escaped Characters
                      All the escape sequences that match a single character, or a single character class are permitted within a character class definition. For example [[]] would match either of [ or ] while [\W\d] would match any character that is either a “digit”, or is not a “word” character.

                      Since \R doesn’t match a “single character” (it can match a single character or a pair of characters more than one character, see boost’s “Matching Line Endings” section), it doesn’t fall within the allowable escape sequences permitted in the character class.

                      edit: while typing this up, four more posts were made. Hopefully, I still added to the discussion.
                      edit 2: clarify the \R

                      Alan Kilborn 1 Reply Last reply Reply Quote 4
                      • Alan Kilborn
                        Alan Kilborn @PeterJones last edited by

                        @PeterJones said:

                        Hopefully, I still added to the discussion.

                        You did, and you helped make it an “interesting discussion”. thanks.

                        1 Reply Last reply Reply Quote 1
                        • glossar
                          glossar last edited by

                          Alan, the second one that finds no-tab :), works, thank you.

                          Guy and Peter - Thank you for stepping-in! :) Much appreciated!

                          Have a nice day!

                          1 Reply Last reply Reply Quote 3
                          • guy038
                            guy038 last edited by guy038

                            Hi, @glossar, @alan-kilborn, @meta-chuh, @peterjones, and All,

                            Here is an other solution, which looks for all contents of lines containing, at least , 2 tabulation chars ( can’t do shorter ! ) :

                            SEARCH (?-s).*\t.*\t.*

                            Just for information, an other formulation of the Alan’s regex, which searches lines which do not contain any tabulation char, could be :

                            SEARCH (?!.*\t)^.+


                            Negative character classes are often misunderstood, Indeed ! When you’re using, for instance, the negative class character below :

                            [^<char1><char2><char3>-<char4>]

                            It will match ANY Unicode character which is DIFFERENT from, either <char1>, <char2> and all characters between <char3> and <char4> included. So, most of the time, it probably matches the \r and \n END of Line characters. To avoid matching these line-break chars, just insert \r and \n, inside the negative class, at any location, after the ^, except in ranges :

                            [^<char1>\n<char2>\t<char3>-<char4>]

                            Cheers,

                            guy038

                            1 Reply Last reply Reply Quote 3
                            • glossar
                              glossar @Alan Kilborn last edited by glossar

                              @Alan-Kilborn said:

                              @glossar said:

                              regex that locates a line that contains no tab?

                              There might be better ones, but this one seems to work:

                              ^((?!\t).)*$

                              Hi @alan-kilborn,
                              Is it possible for you to modify this regex so shat it should skip blank lines, i.e. the ones containing no characters at all, just (if applicable, ^ and) \r\n. Currently the regex finds blank lines as well since they , too, meet the criteria “no-tab”.

                              Thanks in advance!

                              Alan Kilborn 1 Reply Last reply Reply Quote 0
                              • guy038
                                guy038 last edited by guy038

                                Hi, @glossar, @alan-kilborn, @meta-chuh, @peterjones, and All,

                                I may be mistaken but I think that the regex (?!.*\t)^.+, of my previous post, just meet your needs, doesn’t it ?

                                Cheers,

                                guy038

                                1 Reply Last reply Reply Quote 4
                                • Alan Kilborn
                                  Alan Kilborn @glossar last edited by

                                  @glossar said:

                                  Is it possible for you to modify this regex so shat it should skip blank lines

                                  So we should look at what the original means:

                                  ^((?!\t).)*$

                                  It says (basically) to match zero or more occurrences (because of the use of *) of anything that is not TAB. If we change it to match ONE or more occurrences (we’re going to change * to + to do this) of anything that is not TAB). Because we have to match at least ONE thing, empty/blank lines are no longer matched:

                                  ^((?!\t).)+$

                                  Which is basically what @guy038 said, but I wanted to elaborate a bit!

                                  1 Reply Last reply Reply Quote 2
                                  • guy038
                                    guy038 last edited by

                                    Hi, @glossar, @alan-kilborn, @meta-chuh, @peterjones and All,

                                    Fundamentally, the new Alan’s solution and mine give the same right results, i.e. to match any non-empty line which does not contain a tabulation character !

                                    By the way, we, both, forget to add the leading in-line-modifier (?-s) to be sure that, even you previously ticked the . matches newline option, the regex engine will suppose that any . char does match a single standard character, only !

                                    So, our two solutions should be :

                                    Alan : (?-s)^((?!\t).)+$

                                    Guy : (?-s)(?!.*\t)^.+


                                    However, note that the logic, underlying these 2 regular expressions, is a bit different :

                                    • In the Alan’s regex, from beginning of line ( ^ ), the regex engine matches for one or more standard characters, till the end of line ( $ ), ONLY IF each standard character encountered is not a tabulation character, due to the negative look-ahead (?!\t), located right before the . regex character

                                    • In the Guy’s regex, the regex engine matches for all the standard characters of a line, ( ^.+ ), ONLY IF ( implicitly at beginning of line ) it cannot find a tabulation character further on, at any position of current line, due to the negative look-ahead (?!.*\t)

                                    I did a test with a file of 2,500,000 lines, half of which contained 1 tabulation character and, clearly, the Alan’s version is faster ! ( 2 mn 15 s for Alan instead of 5mn for my version )

                                    BR

                                    guy038

                                    1 Reply Last reply Reply Quote 2
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