# How to prevent duplicate tags in Websources Script?
**URL:** https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417
**Category:** Web Sources Discussion
**Created:** [February 21, 2022, 9:10am UTC](https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417 "2022-02-21T09:10:00Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [February 21, 2022, 9:10am UTC](https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417/1 "2022-02-21T09:10:01Z")
I am facing the following problem in a Websources Script:
When I loop through a JSON result file with this code snippet
```auto
OutputTo "SOLOIST" # A Solo artist can play the same instrument on different days
json_select "artist" # therefore he/she appears multiple times on a MusicBrainz recording
json_foreach "artist"
json_select "name"
SayRest
json_foreach_end
```
the content for the SOLOIST-per-recording in the Websource script looks like this:
`|Isaac Stern\\Alexander Zakin\\Isaac Stern\\Alexander Zakin\\`
As you can see, the artists are doubled in this case. As soon as applied, this creates 4 SOLOIST tags
SOLOIST Isaac Stern
SOLOIST Alexander Zakin
SOLOIST Isaac Stern
SOLOIST Alexander Zakin
_This is an example. A Solo artist could appear many more times and in random sort order._
**Do you know a Webscript way to prevent writing such identical information into tags?**
The de-duplicated content should look like this for the above case, showing every Solo artist only once:
SOLOIST Isaac Stern
SOLOIST Alexander Zakin
With this regular expression (used in a Mp3tag Action, after using the Webscript)
`$regexp($meta_sep(SOLOIST,\\),'(\b\w+\b),? ?-? ?(?=.*\1)',)`
we can eliminate the duplicate artists afterwards.
But I would rather detect it already in the source script and prefer not to write into the tracks at all.
**Any idea how to do that?**
---
### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [July 22, 2025, 7:53am UTC](https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417/2 "2025-07-22T07:53:53Z")
> [@LyricsLover](#):
>
> `$regexp($meta_sep(SOLOIST,\\),'(\b\w+\b),? ?-? ?(?=.*\1)',)`
I just found a case where this doesn't work as expected.
If the Name is the same for two SOLOIST (as "Amott" in this example)
the first entry will be reduced to:
Please let me know if there is a way to reduce duplicate entries in a Websources Script.
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [July 22, 2025, 8:46am UTC](https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417/3 "2025-07-22T08:46:33Z")
> [@LyricsLover](#):
>
> Please let me know if there is a way to reduce duplicate entries in a Websources Script.
It's unfortunately currently not possible from a Web Source.
You'd have to run an action **Remove duplicate fields** with **Only duplicated fields with same content** enabled to post-process the data.
---
### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [July 22, 2025, 8:54am UTC](https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417/4 "2025-07-22T08:54:35Z")
Thank you @Florian
The mentioned Action
for above example produces the expected 5 (deduplicated) SOLOIST fields:
---
### Author:  [@yorickausyps](https://community.mp3tag.de/u/yorickausyps)
#### Post date: [August 4, 2025, 9:05am UTC](https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417/5 "2025-08-04T09:05:34Z")
The deduplication for e.g. names in a list can be done in a websource script in the following way.
Before we store the new name in the output buffer `“soloist”` containing the list of names we have to check if it is already in this output buffer.
The command `findinline` seems to do right that, but unfortunately it works the other way around: It finds a given string in the current input line. Because we are searching for a string in another output buffer, we first have to exchange the contents of the two buffers.
We store the new name into in a temporary used output buffer `“temp_name”` and then load the content of the output buffer `“soloist”` with the command `regexpreplace "^.*" "%soloist%"` in the current input line.
But two more things have to be taken care of:
To actually test if the command `findinline` has found a match we mark the end of the line with a vertical bar `|` and to avoid a substring to trigger a match we have to enclose the strings with our delimiter `\\`.
Your example now can be extended like that:
```auto
set "SOLOIST"
json_select "artist"
json_foreach "artist"
json_select "name"
set "temp_name"
outputto "temp_name"
SayRest
regexpreplace "^.*" "\\\\%soloist%\\\\|"
findinline "\\%temp_name%\\" 1 1
movechar -1
if "|"
outputto "soloist"
ifoutput "soloist"
say "\\\\"
endif
sayoutput "temp_name"
endif
json_foreach_end
```
It uses the new feature available since version 3.23 to reference contents of output buffers via `%output%` in all string parameters.
The "feature" to overload the input line with the `regexreplace "^.*" "string"` is very valuable for writing websource scripts, that do "currently impossible" things.
Hope this helps.
PS The number of backslashs was not correct. Thanks to [Output referral and special characters - #2 by rboss](https://community.mp3tag.de/t/output-referral-and-special-characters/67947/2)
---
### Author:  [@rboss](https://community.mp3tag.de/u/rboss)
#### Post date: [August 11, 2025, 8:49pm UTC](https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417/6 "2025-08-11T20:49:32Z")
> [@LyricsLover](#):
>
> Do you know a Webscript way to prevent writing such identical information into tags?
I've ran into a similar situation on a MB script of mine, where I wanted to remove duplicates of media entries for music collections. On the cases where there were -let's say- 7x CD + 3x Blu-Ray + 1x vinyl, at some point I would end up with a string like:
`"CD,CD,CD,CD,CD,CD,CD,Blu-Ray,Blu-Ray,Blu-Ray,Vinyl"`
But for an index I was only interested in the medium _type_ and not _number_, so only 1 of each medium was desired.
I also wanted an efficient solution: preferably without leaving the current buffer output, avoiding JSON commands (if possible), and using a minimum amount of commands.
Here's what I came up with:
```auto
RegexpReplace "^.*" ",${0},#"
Do
FindInLine "," 1 1
IfNot "#"
OutputTo "str0"
SayUntil ","
Replace "%str0%," ""
RegexpReplace "^.*" "${0}, %str0%"
Set "str0"
EndIf
While ","
Replace ",#, " ""
```
Breakdown:
The first regex adds a leading delimiter matching those in the string, and a trailing delimiter + 'break' character to escape the loop.
Then a `Do... While` to do the following (on each loop):
- read one entry (up to its respective delimiter) into a temporary output;
- use `Replace` to remove ALL instances of the entry from the string (including delimiters);
- append 1 instance of the removed entry(ies) to the end of the string (past the break character);
- reset the temporary output.
At the end of the loop, the string becomes something like
`",#, CD, Blu-Ray, Vinyl"`
where a final `Replace ",#, " ""` removes the leading unnecessary characters + whitespace.
I think there's room for improvements, but -with some modifications- a similar approach might work for your current problem.
Hope this helps.
---
### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [September 10, 2025, 8:50pm UTC](https://community.mp3tag.de/t/how-to-prevent-duplicate-tags-in-websources-script/56417/7 "2025-09-10T20:50:01Z")
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.