Regexp replace to match a string, but not match a superstring












3















Let's say I want to replace the string "Vector" by "VectorBase", but there are existing instances of "VectorBase". So I would like to omit "VectorBase". What is an elegant way to achieve this?



An easy way is to do ignore the condition and do the replacement and at the end replace all instances of BaseBase by Base. I'm looking for a better way to achieve this.






regular-expressions replace query-replace







share|improve this question

























  • What you are looking for is made less clear by your saying that you want an "elegant" way and "a better way", without specifying what you mean by those conditions. Perhaps just ask for a way, and then you can choose which one(s) you think best.

    – Drew
    18 mins ago
















3















Let's say I want to replace the string "Vector" by "VectorBase", but there are existing instances of "VectorBase". So I would like to omit "VectorBase". What is an elegant way to achieve this?



An easy way is to do ignore the condition and do the replacement and at the end replace all instances of BaseBase by Base. I'm looking for a better way to achieve this.






regular-expressions replace query-replace







share|improve this question

























  • What you are looking for is made less clear by your saying that you want an "elegant" way and "a better way", without specifying what you mean by those conditions. Perhaps just ask for a way, and then you can choose which one(s) you think best.

    – Drew
    18 mins ago














3












3








3








Let's say I want to replace the string "Vector" by "VectorBase", but there are existing instances of "VectorBase". So I would like to omit "VectorBase". What is an elegant way to achieve this?



An easy way is to do ignore the condition and do the replacement and at the end replace all instances of BaseBase by Base. I'm looking for a better way to achieve this.






regular-expressions replace query-replace







share|improve this question
















Let's say I want to replace the string "Vector" by "VectorBase", but there are existing instances of "VectorBase". So I would like to omit "VectorBase". What is an elegant way to achieve this?



An easy way is to do ignore the condition and do the replacement and at the end replace all instances of BaseBase by Base. I'm looking for a better way to achieve this.






regular-expressions replace query-replace




regular-expressions replace query-replace






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 19 mins ago









Drew

47.4k462104




47.4k462104










asked 13 hours ago









fermesommefermesomme

200110




200110













  • What you are looking for is made less clear by your saying that you want an "elegant" way and "a better way", without specifying what you mean by those conditions. Perhaps just ask for a way, and then you can choose which one(s) you think best.

    – Drew
    18 mins ago



















  • What you are looking for is made less clear by your saying that you want an "elegant" way and "a better way", without specifying what you mean by those conditions. Perhaps just ask for a way, and then you can choose which one(s) you think best.

    – Drew
    18 mins ago

















What you are looking for is made less clear by your saying that you want an "elegant" way and "a better way", without specifying what you mean by those conditions. Perhaps just ask for a way, and then you can choose which one(s) you think best.

– Drew
18 mins ago





What you are looking for is made less clear by your saying that you want an "elegant" way and "a better way", without specifying what you mean by those conditions. Perhaps just ask for a way, and then you can choose which one(s) you think best.

– Drew
18 mins ago










3 Answers
3






active

oldest

votes


















6














Try bVectorb. The b construct matches the empty string, but only at the beginning and end of a word (what is a "word" depends on the buffer's syntax table however: it should work in most cases, but there might be corner cases that are problematic.)



See Backslash Constructs in Regular Expressions for more information.






share|improve this answer

































    5














    Another simple trick you can use is to match both Vector and VectorBase, and replace them both with VectorBase.



    Vector(Base)? → VectorBase


    More complicated cases can be handled by using elisp in the replacement. For example, the following replaces "Vector" with "Array" unless it was "VectorBase", in which case it 'keeps' it as "VectorBase" (i.e. replaces it with the matched string).



    Vector(Base)? → ,(if 1 & "Array")


    Which is similar (in terms of the end result) to what can be done with arbitrary look-around assertions (in regexp languages which support those).






    share|improve this answer

































      4














      One simple, very old-school way is to do multiple replacement passes:




      1. Replace VectorBase by, say AAAA (some string with chars you're sure don't already occur somewhere).


      2. Replace Vector by VectorBase.


      3. Replace AAAA by VectorBase.



      This works for replace-all and query-replace. It's pretty fail-safe and doesn't require any complex matching or fancy replacement regexp.



      However: It's important that you first check that there are not already some occurrences of any chars of the string you're thinking of using as the temporary replacement (e.g. AAAA). If there are already such occurrences then choose a different string. ;-) (I typically use a string such as ^G (a Control-G character), input in the minibuffer using C-q C-g - after making sure there is no C-g char in the buffer.)






      share|improve this answer





















      • 1





        Even if 'AAAA' doesn't appear in the text, that approach may fail. If the text contains AAVectorBase, the sequence of events described above will result in the text containing VectorBaseAA.

        – Abigail
        7 hours ago











      • @Abigail: Yes, of course. Use a string that has no chars used anywhere. Updated to make that clear. Thx.

        – Drew
        6 hours ago













      Your Answer








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      3 Answers
      3






      active

      oldest

      votes








      3 Answers
      3






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      6














      Try bVectorb. The b construct matches the empty string, but only at the beginning and end of a word (what is a "word" depends on the buffer's syntax table however: it should work in most cases, but there might be corner cases that are problematic.)



      See Backslash Constructs in Regular Expressions for more information.






      share|improve this answer






























        6














        Try bVectorb. The b construct matches the empty string, but only at the beginning and end of a word (what is a "word" depends on the buffer's syntax table however: it should work in most cases, but there might be corner cases that are problematic.)



        See Backslash Constructs in Regular Expressions for more information.






        share|improve this answer




























          6












          6








          6







          Try bVectorb. The b construct matches the empty string, but only at the beginning and end of a word (what is a "word" depends on the buffer's syntax table however: it should work in most cases, but there might be corner cases that are problematic.)



          See Backslash Constructs in Regular Expressions for more information.






          share|improve this answer















          Try bVectorb. The b construct matches the empty string, but only at the beginning and end of a word (what is a "word" depends on the buffer's syntax table however: it should work in most cases, but there might be corner cases that are problematic.)



          See Backslash Constructs in Regular Expressions for more information.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited 11 hours ago

























          answered 13 hours ago









          NickDNickD

          2,4511312




          2,4511312























              5














              Another simple trick you can use is to match both Vector and VectorBase, and replace them both with VectorBase.



              Vector(Base)? → VectorBase


              More complicated cases can be handled by using elisp in the replacement. For example, the following replaces "Vector" with "Array" unless it was "VectorBase", in which case it 'keeps' it as "VectorBase" (i.e. replaces it with the matched string).



              Vector(Base)? → ,(if 1 & "Array")


              Which is similar (in terms of the end result) to what can be done with arbitrary look-around assertions (in regexp languages which support those).






              share|improve this answer






























                5














                Another simple trick you can use is to match both Vector and VectorBase, and replace them both with VectorBase.



                Vector(Base)? → VectorBase


                More complicated cases can be handled by using elisp in the replacement. For example, the following replaces "Vector" with "Array" unless it was "VectorBase", in which case it 'keeps' it as "VectorBase" (i.e. replaces it with the matched string).



                Vector(Base)? → ,(if 1 & "Array")


                Which is similar (in terms of the end result) to what can be done with arbitrary look-around assertions (in regexp languages which support those).






                share|improve this answer




























                  5












                  5








                  5







                  Another simple trick you can use is to match both Vector and VectorBase, and replace them both with VectorBase.



                  Vector(Base)? → VectorBase


                  More complicated cases can be handled by using elisp in the replacement. For example, the following replaces "Vector" with "Array" unless it was "VectorBase", in which case it 'keeps' it as "VectorBase" (i.e. replaces it with the matched string).



                  Vector(Base)? → ,(if 1 & "Array")


                  Which is similar (in terms of the end result) to what can be done with arbitrary look-around assertions (in regexp languages which support those).






                  share|improve this answer















                  Another simple trick you can use is to match both Vector and VectorBase, and replace them both with VectorBase.



                  Vector(Base)? → VectorBase


                  More complicated cases can be handled by using elisp in the replacement. For example, the following replaces "Vector" with "Array" unless it was "VectorBase", in which case it 'keeps' it as "VectorBase" (i.e. replaces it with the matched string).



                  Vector(Base)? → ,(if 1 & "Array")


                  Which is similar (in terms of the end result) to what can be done with arbitrary look-around assertions (in regexp languages which support those).







                  share|improve this answer














                  share|improve this answer



                  share|improve this answer








                  edited 8 hours ago

























                  answered 9 hours ago









                  philsphils

                  26.3k23567




                  26.3k23567























                      4














                      One simple, very old-school way is to do multiple replacement passes:




                      1. Replace VectorBase by, say AAAA (some string with chars you're sure don't already occur somewhere).


                      2. Replace Vector by VectorBase.


                      3. Replace AAAA by VectorBase.



                      This works for replace-all and query-replace. It's pretty fail-safe and doesn't require any complex matching or fancy replacement regexp.



                      However: It's important that you first check that there are not already some occurrences of any chars of the string you're thinking of using as the temporary replacement (e.g. AAAA). If there are already such occurrences then choose a different string. ;-) (I typically use a string such as ^G (a Control-G character), input in the minibuffer using C-q C-g - after making sure there is no C-g char in the buffer.)






                      share|improve this answer





















                      • 1





                        Even if 'AAAA' doesn't appear in the text, that approach may fail. If the text contains AAVectorBase, the sequence of events described above will result in the text containing VectorBaseAA.

                        – Abigail
                        7 hours ago











                      • @Abigail: Yes, of course. Use a string that has no chars used anywhere. Updated to make that clear. Thx.

                        – Drew
                        6 hours ago


















                      4














                      One simple, very old-school way is to do multiple replacement passes:




                      1. Replace VectorBase by, say AAAA (some string with chars you're sure don't already occur somewhere).


                      2. Replace Vector by VectorBase.


                      3. Replace AAAA by VectorBase.



                      This works for replace-all and query-replace. It's pretty fail-safe and doesn't require any complex matching or fancy replacement regexp.



                      However: It's important that you first check that there are not already some occurrences of any chars of the string you're thinking of using as the temporary replacement (e.g. AAAA). If there are already such occurrences then choose a different string. ;-) (I typically use a string such as ^G (a Control-G character), input in the minibuffer using C-q C-g - after making sure there is no C-g char in the buffer.)






                      share|improve this answer





















                      • 1





                        Even if 'AAAA' doesn't appear in the text, that approach may fail. If the text contains AAVectorBase, the sequence of events described above will result in the text containing VectorBaseAA.

                        – Abigail
                        7 hours ago











                      • @Abigail: Yes, of course. Use a string that has no chars used anywhere. Updated to make that clear. Thx.

                        – Drew
                        6 hours ago
















                      4












                      4








                      4







                      One simple, very old-school way is to do multiple replacement passes:




                      1. Replace VectorBase by, say AAAA (some string with chars you're sure don't already occur somewhere).


                      2. Replace Vector by VectorBase.


                      3. Replace AAAA by VectorBase.



                      This works for replace-all and query-replace. It's pretty fail-safe and doesn't require any complex matching or fancy replacement regexp.



                      However: It's important that you first check that there are not already some occurrences of any chars of the string you're thinking of using as the temporary replacement (e.g. AAAA). If there are already such occurrences then choose a different string. ;-) (I typically use a string such as ^G (a Control-G character), input in the minibuffer using C-q C-g - after making sure there is no C-g char in the buffer.)






                      share|improve this answer















                      One simple, very old-school way is to do multiple replacement passes:




                      1. Replace VectorBase by, say AAAA (some string with chars you're sure don't already occur somewhere).


                      2. Replace Vector by VectorBase.


                      3. Replace AAAA by VectorBase.



                      This works for replace-all and query-replace. It's pretty fail-safe and doesn't require any complex matching or fancy replacement regexp.



                      However: It's important that you first check that there are not already some occurrences of any chars of the string you're thinking of using as the temporary replacement (e.g. AAAA). If there are already such occurrences then choose a different string. ;-) (I typically use a string such as ^G (a Control-G character), input in the minibuffer using C-q C-g - after making sure there is no C-g char in the buffer.)







                      share|improve this answer














                      share|improve this answer



                      share|improve this answer








                      edited 16 mins ago

























                      answered 12 hours ago









                      DrewDrew

                      47.4k462104




                      47.4k462104








                      • 1





                        Even if 'AAAA' doesn't appear in the text, that approach may fail. If the text contains AAVectorBase, the sequence of events described above will result in the text containing VectorBaseAA.

                        – Abigail
                        7 hours ago











                      • @Abigail: Yes, of course. Use a string that has no chars used anywhere. Updated to make that clear. Thx.

                        – Drew
                        6 hours ago
















                      • 1





                        Even if 'AAAA' doesn't appear in the text, that approach may fail. If the text contains AAVectorBase, the sequence of events described above will result in the text containing VectorBaseAA.

                        – Abigail
                        7 hours ago











                      • @Abigail: Yes, of course. Use a string that has no chars used anywhere. Updated to make that clear. Thx.

                        – Drew
                        6 hours ago










                      1




                      1





                      Even if 'AAAA' doesn't appear in the text, that approach may fail. If the text contains AAVectorBase, the sequence of events described above will result in the text containing VectorBaseAA.

                      – Abigail
                      7 hours ago





                      Even if 'AAAA' doesn't appear in the text, that approach may fail. If the text contains AAVectorBase, the sequence of events described above will result in the text containing VectorBaseAA.

                      – Abigail
                      7 hours ago













                      @Abigail: Yes, of course. Use a string that has no chars used anywhere. Updated to make that clear. Thx.

                      – Drew
                      6 hours ago







                      @Abigail: Yes, of course. Use a string that has no chars used anywhere. Updated to make that clear. Thx.

                      – Drew
                      6 hours ago




















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