changing the first occurrence only of a string in a line
How would you do the following in Rev? We have a file consisting of records with tab separated fields. Each field has a tag followed by contents. Some tags occur more than once in some records which thus have varying numbers of fields. Duplicates are always consecutive. I want to eliminate all the occurrences of any tag except the first one. The duplicate tags can occur any place in the record, but if they are duplicated, will always be consecutive. Doing this in SED is not particularly difficult, but it does require going out to shell, and so its not cross platform. You just change the tag using the local scope to something else. SED then only changes the first occurrence in a record. Then you use the global scope and change all of them. Then you go back and change the first one back to what it was. In fact, if using SED like this, the only thing you need it for is to do the local, first tag, change - once this is done, the rest can be done in Rev. But it would be nice to stay in Rev for the whole thing. Is there a way in Rev to pick the first occurence of a string in a record, change it and not subsequent occurences, and then move on to the next record and do the same thing? That is, mimic the 'local' editing mode of SED? Bet you all thought them dinosaurs like SED had to be extinct by now! But no, they are still trampling around in the swamps of text manipulation For the sake of clarity, a record might look like this: A aa TAB B bb TAB B bb TAB B bb TAB C cc TAB D dd TAB D dd and what is wanted is to change the first occurrence of B to, for example !1, and the first occurence of D to, for example !2, or anyway something that will not occur by chance, to allow the subsequent editing to work globally on the file. This is what SED does in local mode. Peter ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: changing the first occurrence only of a string in a line
Peter, given the sample you provide, I believe this will work: on mouseUp put A aa TAB B bb TAB B bb TAB B bb TAB C cc TAB D dd TAB D dd cr after tData put A aa TAB B bb TAB B bb TAB B bb TAB C cc TAB D dd TAB D dd cr after tData --replace TAB with tab in tData put B 1! cr after tSubs put C 2! cr after tSubs set the wholematches to true repeat for each line tLine in tSubs put word 1 of tLine into tFind put word 2 of tLine into tSubstitute put wordoffset(tFind,tData) into tFoundPos if tFoundPos 0 then put tSubstitute into word tFoundPos of tData end if end repeat put tData end mouseUp However, one of the frustrating things about Rev is that the PCRE engine behind replaceText and matchText is so poorly documented. For example, replaceText can have its functionality altered by the inclusion of modifiers such as (?i) for case insensitive and (?m) for multiline. There are other modifiers (http://uk.php.net/manual/en/reference.pcre.pattern.modifiers.php) some of which are unacceptable, and others that seem to be acceptable. Nowhere have I found these documented with regard to Rev. The (?A) anchored modifier (if it was one of the acceptable tokens) may have worked in your case, but it is apparently unnaceptable. Really you ought to just be able to take your SED expressions and use them with replaceText, as SED expressions are regex AFAIK. There may be some differences between SED and pcre, but since the differences between pcre and Rev are not documented it is vexatious. Bernard On Fri, Jun 19, 2009 at 7:33 AM, Peter Alcibiadespalcibiades-fi...@yahoo.co.uk wrote: How would you do the following in Rev? We have a file consisting of records with tab separated fields. Each field has a tag followed by contents. Some tags occur more than once in some records which thus have varying numbers of fields. Duplicates are always consecutive. I want to eliminate all the occurrences of any tag except the first one. The duplicate tags can occur any place in the record, but if they are duplicated, will always be consecutive. Doing this in SED is not particularly difficult, but it does require going out to shell, and so its not cross platform. You just change the tag using the local scope to something else. SED then only changes the first occurrence in a record. Then you use the global scope and change all of them. Then you go back and change the first one back to what it was. In fact, if using SED like this, the only thing you need it for is to do the local, first tag, change - once this is done, the rest can be done in Rev. But it would be nice to stay in Rev for the whole thing. Is there a way in Rev to pick the first occurence of a string in a record, change it and not subsequent occurences, and then move on to the next record and do the same thing? That is, mimic the 'local' editing mode of SED? Bet you all thought them dinosaurs like SED had to be extinct by now! But no, they are still trampling around in the swamps of text manipulation For the sake of clarity, a record might look like this: A aa TAB B bb TAB B bb TAB B bb TAB C cc TAB D dd TAB D dd and what is wanted is to change the first occurrence of B to, for example !1, and the first occurence of D to, for example !2, or anyway something that will not occur by chance, to allow the subsequent editing to work globally on the file. This is what SED does in local mode. Peter ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: changing the first occurrence only of a string in a line
I'm not going toanswer your direct question (replace first occurrence) because that is a subset of the whole question, which I think is more interesting :-) How would I remove the duplicates as described below ? (I have assumed that in each field the tag is separated from the content by a space, so used 'word' to extract the tag) [I tested this in the msg box] put A aaa tab B bbb tab B bb2 C ccc cr into tData put A a2a tab B b2b tab B 2b2 C ccc tab C cc2 cr after tData set the itemDel to tab repeat for each line L in tData put empty into lastTag put empty into tLine repeat for each item itm in L if word 1 of itm lastTag then put itm tab after tLine put word 1 of itm into lastTag end if end repeat delete the last char of tLine -- trailing tab character put tLine cr afer tOutput end repeat put tOutput -- Alex. Peter Alcibiades wrote: How would you do the following in Rev? We have a file consisting of records with tab separated fields. Each field has a tag followed by contents. Some tags occur more than once in some records which thus have varying numbers of fields. Duplicates are always consecutive. I want to eliminate all the occurrences of any tag except the first one. The duplicate tags can occur any place in the record, but if they are duplicated, will always be consecutive. Doing this in SED is not particularly difficult, but it does require going out to shell, and so its not cross platform. You just change the tag using the local scope to something else. SED then only changes the first occurrence in a record. Then you use the global scope and change all of them. Then you go back and change the first one back to what it was. In fact, if using SED like this, the only thing you need it for is to do the local, first tag, change - once this is done, the rest can be done in Rev. But it would be nice to stay in Rev for the whole thing. Is there a way in Rev to pick the first occurence of a string in a record, change it and not subsequent occurences, and then move on to the next record and do the same thing? That is, mimic the 'local' editing mode of SED? Bet you all thought them dinosaurs like SED had to be extinct by now! But no, they are still trampling around in the swamps of text manipulation For the sake of clarity, a record might look like this: A aa TAB B bb TAB B bb TAB B bb TAB C cc TAB D dd TAB D dd and what is wanted is to change the first occurrence of B to, for example !1, and the first occurence of D to, for example !2, or anyway something that will not occur by chance, to allow the subsequent editing to work globally on the file. This is what SED does in local mode. ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
