Regexp replace to to match a string, but not 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





























    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



























      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 9 hours ago









      Drew

      47.4k462104




      47.4k462104










      asked 10 hours ago









      fermesommefermesomme

      200110




      200110






















          3 Answers
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          active

          oldest

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          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 that you're sure doesn'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
                4 hours ago











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

                – Drew
                3 hours ago













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              3 Answers
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              3 Answers
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              active

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              active

              oldest

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              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 8 hours ago

























                  answered 10 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 5 hours ago

























                          answered 6 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 that you're sure doesn'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
                                4 hours ago











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

                                – Drew
                                3 hours ago


















                              4














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




                              1. Replace VectorBase by, say AAAA (some string that you're sure doesn'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
                                4 hours ago











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

                                – Drew
                                3 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 that you're sure doesn'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 that you're sure doesn'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 3 hours ago

























                              answered 9 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
                                4 hours ago











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

                                – Drew
                                3 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
                                4 hours ago











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

                                – Drew
                                3 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
                              4 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
                              4 hours ago













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

                              – Drew
                              3 hours ago







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

                              – Drew
                              3 hours ago




















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