# Function to reverse Filter **URL:** https://community.mp3tag.de/t/function-to-reverse-filter/16629 **Category:** General Discussion **Created:** [February 25, 2015, 8:06pm UTC](https://community.mp3tag.de/t/function-to-reverse-filter/16629 "2015-02-25T20:06:37Z") **Posts on this page:** 1 **Showing post:** 13
### Author: ![Zerow](https://community.mp3tag.de/user_avatar/community.mp3tag.de/zerow/32/11379_2.png) [@Zerow](https://community.mp3tag.de/u/Zerow) #### Post date: [November 28, 2019, 7:32pm UTC](https://community.mp3tag.de/t/function-to-reverse-filter/16629/13 "2019-11-28T19:32:48Z")
> [@ohrenkino](#): > > [...] > In respect to the numbers I have some questions: > What is the criterion of numbering them? > The loading order? > The current sorting order? The moment a file is loaded up it should gain a number- and that is it If you somehow sort them out, the sort order would hold out- just like it does now whenever you enter anything into Filter box; does it not? And if you in Mp3tag delete or remove a file temporarily numbered `125`- then it is simply removed from that temporary list. And then when you add a new one- then it becomes [e.g.] "file #10001" and not "file #125 but new" [or it could indeed take the now missing number - but that is for the programmer to decide what would work better] > [@ohrenkino](#): > > [...] > What happens when you press the "reverse button" to files that have been editted so that they do not match the "positive" filter any more but should belong to the "reverse" list? When you go back from using `reverse` to normal- the filter expression is then either applied once more [which could take time, which would be a downside] or the `positive` [normal] files are shown from the memory / list- and that choice behavior could be configurable as well [just like in case of `Auto-apply` option being turned on / off]. That second option would of course show then also the missing files- so it would misinform the user But such ghost / blank files already are capable of existing in Mp3tag. Here is a proof: > [@Keep track of moved files also when aborting the operation](https://community.mp3tag.de/t/lost-of-track-of-moved-files-and-turning-them-into-ghost-files/47099): > > How to replicate his bug: 1] Load at least 2 files, one of them other than MP3 2] Play that non-MP3 file in your player 3] Select both of files 4] Choose for them Move... from the right click menu 5] When prompted by operating system about that one file being in use [by the player] choose Skip or Cancel 6] When prompted by Mp3tag about re-reading of the directory choose No What happens? Mp3tag looses from sight both of the files, leaving on the list of files empty "files"; ghosts, s… > [@ohrenkino](#): > > Will the "reverse" list be updated with editted files? Reverse would always be created when filtering expression would be entered or changed. With 100 000 files it will take time- so some kind of progress bar indicating that would make it possible for the use to see if the reverse is ready to be pushed. Or instead of progress bar a simple grayed out Reverse button turning green [or whatever other color / form]] would tell the same thing > [@ohrenkino](#): > > What is the purpose of the numbers anyway? > Should I memorize the numbers so that I know which file was in which list? > Should I scan through lengthy lists to see where there is a gap? > [....] Do you memorize the `FILENAME`s of what you drag and drop to Mp3tag in order to be able to filter them later on? Purpose of number? To id them. So that the Mp3tag would now that file #567 was not shown when filtering expression was entered- which would automatically mean that when the reverse option is activated, file 567 is to be shown. [And to avoid another question] When another expression would be entered, that file would still have this number. And if this time it would show in the normal mode, then it would be not as much as removed from the list- but the list would be created from scratch- is it not what now is happening: you change expression in the Filter box thus you change the outcome shown in the main window. The difference is that now a list [be it for positives or negatives] is not created in a form of file --- _[View the full topic](https://community.mp3tag.de/t/function-to-reverse-filter/16629)._