Python regex error: “cannot refer to an open group”









up vote
-1
down vote

favorite












I am creating rules for a reddit automoderator. It gets its rules from a YAML config file and the regexes are interpreted as Python regex.



I am trying to make the following regular expression work:



(https?://[\w\d:#@%/;$()~_?+-=\.&]+\.\w2,6)([\S\s]*\1)


When I test it on https://pythex.org/ it works perfectly to achieve what I want.



Unfortunately my group reference at the end of the expression is causing an error when I copy the same regex into the config file:




Generated an invalid regex for body (regex): cannot refer to an open
group




I have also tried this version with everything escaped just to make sure that the characters weren't interfering in any way:



(https?://[\w\d\:\#\@\%\/\;\$\(\)\~\_\?\+\-\=\.&]+\.\w2,6)([\S\s]*\1)


But I still get the same error. Does anyone know what I'm doing wrong here?










share|improve this question























  • Can you try to print the regex? Also, try it without the ( [Ss]* 1 ) and see if it errors.
    – sln
    Nov 11 at 19:23










  • I cannot print the regex, as I am just setting rules in YAML and they are being interpreted by someone else's python code. It does not have errors without the end group.
    – Patrick Thorpe
    Nov 11 at 19:28










  • That error is thrown if you reference a group inside the group like this so it could be the closing ) is not being seen.
    – sln
    Nov 11 at 19:29










  • Then, remove the end group and just put 1 at the end, as a test.
    – sln
    Nov 11 at 19:30











  • And, it wouldn't hurt to escape the forward slashes for a test ((https?://[wd:#@%/;$()~_?+-=.&]+.w2,6)([Ss]*1) Note that you have to escape the dash in the class if you want it to be literal -
    – sln
    Nov 11 at 19:34















up vote
-1
down vote

favorite












I am creating rules for a reddit automoderator. It gets its rules from a YAML config file and the regexes are interpreted as Python regex.



I am trying to make the following regular expression work:



(https?://[\w\d:#@%/;$()~_?+-=\.&]+\.\w2,6)([\S\s]*\1)


When I test it on https://pythex.org/ it works perfectly to achieve what I want.



Unfortunately my group reference at the end of the expression is causing an error when I copy the same regex into the config file:




Generated an invalid regex for body (regex): cannot refer to an open
group




I have also tried this version with everything escaped just to make sure that the characters weren't interfering in any way:



(https?://[\w\d\:\#\@\%\/\;\$\(\)\~\_\?\+\-\=\.&]+\.\w2,6)([\S\s]*\1)


But I still get the same error. Does anyone know what I'm doing wrong here?










share|improve this question























  • Can you try to print the regex? Also, try it without the ( [Ss]* 1 ) and see if it errors.
    – sln
    Nov 11 at 19:23










  • I cannot print the regex, as I am just setting rules in YAML and they are being interpreted by someone else's python code. It does not have errors without the end group.
    – Patrick Thorpe
    Nov 11 at 19:28










  • That error is thrown if you reference a group inside the group like this so it could be the closing ) is not being seen.
    – sln
    Nov 11 at 19:29










  • Then, remove the end group and just put 1 at the end, as a test.
    – sln
    Nov 11 at 19:30











  • And, it wouldn't hurt to escape the forward slashes for a test ((https?://[wd:#@%/;$()~_?+-=.&]+.w2,6)([Ss]*1) Note that you have to escape the dash in the class if you want it to be literal -
    – sln
    Nov 11 at 19:34













up vote
-1
down vote

favorite









up vote
-1
down vote

favorite











I am creating rules for a reddit automoderator. It gets its rules from a YAML config file and the regexes are interpreted as Python regex.



I am trying to make the following regular expression work:



(https?://[\w\d:#@%/;$()~_?+-=\.&]+\.\w2,6)([\S\s]*\1)


When I test it on https://pythex.org/ it works perfectly to achieve what I want.



Unfortunately my group reference at the end of the expression is causing an error when I copy the same regex into the config file:




Generated an invalid regex for body (regex): cannot refer to an open
group




I have also tried this version with everything escaped just to make sure that the characters weren't interfering in any way:



(https?://[\w\d\:\#\@\%\/\;\$\(\)\~\_\?\+\-\=\.&]+\.\w2,6)([\S\s]*\1)


But I still get the same error. Does anyone know what I'm doing wrong here?










share|improve this question















I am creating rules for a reddit automoderator. It gets its rules from a YAML config file and the regexes are interpreted as Python regex.



I am trying to make the following regular expression work:



(https?://[\w\d:#@%/;$()~_?+-=\.&]+\.\w2,6)([\S\s]*\1)


When I test it on https://pythex.org/ it works perfectly to achieve what I want.



Unfortunately my group reference at the end of the expression is causing an error when I copy the same regex into the config file:




Generated an invalid regex for body (regex): cannot refer to an open
group




I have also tried this version with everything escaped just to make sure that the characters weren't interfering in any way:



(https?://[\w\d\:\#\@\%\/\;\$\(\)\~\_\?\+\-\=\.&]+\.\w2,6)([\S\s]*\1)


But I still get the same error. Does anyone know what I'm doing wrong here?







regex regex-group






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 12 at 7:28









Anthon

28.2k1693144




28.2k1693144










asked Nov 11 at 19:13









Patrick Thorpe

6411




6411











  • Can you try to print the regex? Also, try it without the ( [Ss]* 1 ) and see if it errors.
    – sln
    Nov 11 at 19:23










  • I cannot print the regex, as I am just setting rules in YAML and they are being interpreted by someone else's python code. It does not have errors without the end group.
    – Patrick Thorpe
    Nov 11 at 19:28










  • That error is thrown if you reference a group inside the group like this so it could be the closing ) is not being seen.
    – sln
    Nov 11 at 19:29










  • Then, remove the end group and just put 1 at the end, as a test.
    – sln
    Nov 11 at 19:30











  • And, it wouldn't hurt to escape the forward slashes for a test ((https?://[wd:#@%/;$()~_?+-=.&]+.w2,6)([Ss]*1) Note that you have to escape the dash in the class if you want it to be literal -
    – sln
    Nov 11 at 19:34

















  • Can you try to print the regex? Also, try it without the ( [Ss]* 1 ) and see if it errors.
    – sln
    Nov 11 at 19:23










  • I cannot print the regex, as I am just setting rules in YAML and they are being interpreted by someone else's python code. It does not have errors without the end group.
    – Patrick Thorpe
    Nov 11 at 19:28










  • That error is thrown if you reference a group inside the group like this so it could be the closing ) is not being seen.
    – sln
    Nov 11 at 19:29










  • Then, remove the end group and just put 1 at the end, as a test.
    – sln
    Nov 11 at 19:30











  • And, it wouldn't hurt to escape the forward slashes for a test ((https?://[wd:#@%/;$()~_?+-=.&]+.w2,6)([Ss]*1) Note that you have to escape the dash in the class if you want it to be literal -
    – sln
    Nov 11 at 19:34
















Can you try to print the regex? Also, try it without the ( [Ss]* 1 ) and see if it errors.
– sln
Nov 11 at 19:23




Can you try to print the regex? Also, try it without the ( [Ss]* 1 ) and see if it errors.
– sln
Nov 11 at 19:23












I cannot print the regex, as I am just setting rules in YAML and they are being interpreted by someone else's python code. It does not have errors without the end group.
– Patrick Thorpe
Nov 11 at 19:28




I cannot print the regex, as I am just setting rules in YAML and they are being interpreted by someone else's python code. It does not have errors without the end group.
– Patrick Thorpe
Nov 11 at 19:28












That error is thrown if you reference a group inside the group like this so it could be the closing ) is not being seen.
– sln
Nov 11 at 19:29




That error is thrown if you reference a group inside the group like this so it could be the closing ) is not being seen.
– sln
Nov 11 at 19:29












Then, remove the end group and just put 1 at the end, as a test.
– sln
Nov 11 at 19:30





Then, remove the end group and just put 1 at the end, as a test.
– sln
Nov 11 at 19:30













And, it wouldn't hurt to escape the forward slashes for a test ((https?://[wd:#@%/;$()~_?+-=.&]+.w2,6)([Ss]*1) Note that you have to escape the dash in the class if you want it to be literal -
– sln
Nov 11 at 19:34





And, it wouldn't hurt to escape the forward slashes for a test ((https?://[wd:#@%/;$()~_?+-=.&]+.w2,6)([Ss]*1) Note that you have to escape the dash in the class if you want it to be literal -
– sln
Nov 11 at 19:34













1 Answer
1






active

oldest

votes

















up vote
0
down vote



accepted










I managed to fix the problem by changing the group selection to 2 instead of 1.



It turned out that YAML or AutoModerator were automatically putting parentheses around the whole expression, so any group references within must be 1 more than you would initially expect.



I had thought that this was the problem at the start, and tried the fix explained above, however due to a separate issue with the AutoModerator code, the fix had not appeared to have worked. All resolved now though; thanks for your patience and help.






share|improve this answer




















    Your Answer






    StackExchange.ifUsing("editor", function ()
    StackExchange.using("externalEditor", function ()
    StackExchange.using("snippets", function ()
    StackExchange.snippets.init();
    );
    );
    , "code-snippets");

    StackExchange.ready(function()
    var channelOptions =
    tags: "".split(" "),
    id: "1"
    ;
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function()
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled)
    StackExchange.using("snippets", function()
    createEditor();
    );

    else
    createEditor();

    );

    function createEditor()
    StackExchange.prepareEditor(
    heartbeatType: 'answer',
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader:
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    ,
    onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    );



    );













    draft saved

    draft discarded


















    StackExchange.ready(
    function ()
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53252249%2fpython-regex-error-cannot-refer-to-an-open-group%23new-answer', 'question_page');

    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    0
    down vote



    accepted










    I managed to fix the problem by changing the group selection to 2 instead of 1.



    It turned out that YAML or AutoModerator were automatically putting parentheses around the whole expression, so any group references within must be 1 more than you would initially expect.



    I had thought that this was the problem at the start, and tried the fix explained above, however due to a separate issue with the AutoModerator code, the fix had not appeared to have worked. All resolved now though; thanks for your patience and help.






    share|improve this answer
























      up vote
      0
      down vote



      accepted










      I managed to fix the problem by changing the group selection to 2 instead of 1.



      It turned out that YAML or AutoModerator were automatically putting parentheses around the whole expression, so any group references within must be 1 more than you would initially expect.



      I had thought that this was the problem at the start, and tried the fix explained above, however due to a separate issue with the AutoModerator code, the fix had not appeared to have worked. All resolved now though; thanks for your patience and help.






      share|improve this answer






















        up vote
        0
        down vote



        accepted







        up vote
        0
        down vote



        accepted






        I managed to fix the problem by changing the group selection to 2 instead of 1.



        It turned out that YAML or AutoModerator were automatically putting parentheses around the whole expression, so any group references within must be 1 more than you would initially expect.



        I had thought that this was the problem at the start, and tried the fix explained above, however due to a separate issue with the AutoModerator code, the fix had not appeared to have worked. All resolved now though; thanks for your patience and help.






        share|improve this answer












        I managed to fix the problem by changing the group selection to 2 instead of 1.



        It turned out that YAML or AutoModerator were automatically putting parentheses around the whole expression, so any group references within must be 1 more than you would initially expect.



        I had thought that this was the problem at the start, and tried the fix explained above, however due to a separate issue with the AutoModerator code, the fix had not appeared to have worked. All resolved now though; thanks for your patience and help.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 11 at 20:27









        Patrick Thorpe

        6411




        6411



























            draft saved

            draft discarded
















































            Thanks for contributing an answer to Stack Overflow!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid


            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.

            To learn more, see our tips on writing great answers.





            Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


            Please pay close attention to the following guidance:


            • Please be sure to answer the question. Provide details and share your research!

            But avoid


            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.

            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53252249%2fpython-regex-error-cannot-refer-to-an-open-group%23new-answer', 'question_page');

            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            這個網誌中的熱門文章

            How to read a connectionString WITH PROVIDER in .NET Core?

            Node.js Script on GitHub Pages or Amazon S3

            Museum of Modern and Contemporary Art of Trento and Rovereto