Adding duplicate title in title list

[andres....@gmail.com]

Ok, so I have the following list:

    foo foo foo bar

I then want to append 'foo' to the end of that list such that I wind up with:

    foo foo foo bar foo

So I try the following filter:

    [[foo foo foo bar]enlist-input:raw[]] [[foo]]

That results in:

    foo foo bar foo

This is unexpected to me, which means that there is something I don't understand.

So I have two questions:

1. Why is the title not appended as I expected?

2. How can I get the result I want? To add complexity (cause why not?), the list will be generated dynamically based on user input, titles will only sometimes be of existing tiddlers, and the titles can have spaces xD.

[andres....@gmail.com]

I should add that the list is currently stored as a field, so my filter is more along the lines of

[all[current]get[fieldName]enlist-input:raw[]] [<addedTitle>]

I couldn't use the listops action widget subfilters because they automatically dedup so I need to use the full filter which doesn't fully dedup my list but, at least with this filter, still makes me lose entries.

[Eric Shulman]

Answer to question #1:

By default, titles resulting from a filter are only listed once, with the last instance of a given title "dominantly appended" to the list (i.e., duplicates are removed).  Thus, in your example, adding `[[foo]]` to the end of the list automatically removed the first instance of `foo` from the front of the list.  You've already discovered the use of the `:raw` suffix for the `enlist-input` operator, which prevents duplicates from being removed when you enlist an existing space-separated list.  Another bit of filter syntax that helps with preserving duplicates is the "=" prefix on a filter run.  To get the results you expected, you would write: `[[foo foo foo bar]enlist-input:raw[]] =[[foo]]`.

Answer to question #2:

As you noted in your followup message, you have an existing list stored in a tiddler field called `fieldName`.  Let's assume this field contains 4 items: `foo [[bar baz]] mumble [[frotz gronk snork]]` (where the 2nd and 4th items contain spaces).  To add an item to that list, you would write something like this:: `[<currentTiddler>get[fieldName]enlist-input:raw[]] =[<addedTitle>]`.  Note also that using `<currentTiddler>` in your filter is *slightly* more efficient than `all[current]`, since the `all[]` operator first needs to parse the operand (`current`) to determine that you want to retrieve the current tiddler's title, while `<currentTiddler>` directly retrieves the title without the added internal layer of parsing.

enjoy,

-e

[andres....@gmail.com]

Amazing response, Eric. Thank you!

That worked perfectly! I need to spend some quality time with https://tiddlywiki.com/#Filter%20Expression. There is a lot of new stuff on there I hadn't seen before!

> Note also that using `<currentTiddler>` in your filter is *slightly* more efficient than `all[current]`

See, I used to use currentTiddler but saw so many examples with all[current] that I assumed that there was some optimization going on there. Noted and adjusted. Great tip!

> enjoy

I will, thank you!