Using the number twice in numbered list format

I would like to format a numbered list as follows:

  1. Article 1: Foo
  2. Article 2: Bar
  3. Article 3: Baz

The prefix "N. Article N: " should be automatic.

OS: Windows 10.0 Build 19044
LO: Version: (x64)

Context: The document is a list of articles. Some may be inserted and some may be deleted, so it is preferable that the numbering updates automatically. The idea is to have the numbers appear in a margin as well in order to make it easier to identify the current position when reading. That is what the first “1.” is for. It makes most sense to me that the leading “1.” is the primary number.

But regardless of the context, I want to know if I can use the list number multiple times in a format, much like the format code in LO Calc for formatting dates where you can in principle do DD/MM/YY/DD.

Skill level: anything is fine, I’m sure I’ll figure it out. I’m coming from LaTeX but I want to make this document in LO Writer to accomodate collaborators. Compatibility with MS Word is preferable but not necessary.

There are two (rather contorted) ways of doing it. What is your skill level regarding styles and fields?
But, IMHO, your specification is faulty. Both numbers have not the same semantic value. The first one (1.) is an enumeration index, which is sequential by nature. The second one (Article 1) is the identity of the object and must not change if lines are permuted. For me, they don’t play the same role and should not be related.
In case you stick with your specification, tell which one should be considered the “primary” original number.
Don’t forget to mention your OS name and LO version.
For site cleanliness, prefer to edit your question over starting a conversation.

It is not possible to use directly several times such a number. You have to resort to cross-references. But while experimenting, I bumped into an issue I didn’t expect: the captured number includes the prefix and suffix (Aticle and : I added so that they automatically inserted).
I’ll attach a proposed solution where I reproduce in the margin “Article 1” instead of merely “1”. Stay tuned.

Thanks, I edited my question.

Just for playing, I tried with table and formulas:
number_article_number in table with formulas.odt (23.6 KB).

From row 2 downward I used the formula =<An-1>+1.
When inserting or deleting rows, it is needed to recopy the formula.

Line Numbering could be of little help here.

A workaround including Calc: =ROW()&". Article "&ROW()&":" in the first column, and the article data in the second column. Copy and paste (each time there is a change) in Writer as RTF, then convert table to text.

I would prefer the easy way:
Use negative indent for the first line, so Article 1: lays to the left of the data text.

I’ve come up to a very complicated procedure to be able to get what you describe.

First of all, neither the “1.” not the “Article 1:” is the primary reference in order to get correct list auto numbering.

In the attached AskLODoubleListNbr.odt (19.0 KB), I propose two solutions.

In the first half, I have a “traditional” list with some intermediate unnumbered items. The list uses the Numbering 123 list style I have customized with "Article " prefix.

The number is copied inside a frame (styled MarginNbr). This frame is parameterised so that it lies in the left page border, vertically centered on the paragraph text (modify to your liking). Contents is a cross-reference field to a Numbered paragraph.

As you can see, you can’t get rid of the suffix and prefix defined in the list style.

The list style is the primary numbering source, not the margin frame. I deliberately did it because the inverse would lead to strange numbering sequence: frames are not part of the main flow and are scanned by Writer in a not “consistent” order (something like the timely order of insertion). This results in a non geographic monotonic sequencing. To keep the expected numbering, the list (in the main text flow) must be the primary source.

I tried to be closer your specification in the lower half. It is even trickier than the first solution. Open the file to follow the very concise comments below.

The list is now controlled by Numbering ABC. No prefix nor suffix decorate the “number”. I modified Numbering Symbol character style (used to format the number) to be hidden (but it is ineffective apparently).

The margin echo is done using the same technique as previously except I manually add "Article " before the number because the number is now “undecorated”.

In the text itself, I anchor a ParaNbr-styled frame to the list item. This frame is positioned in the Left paragraph border, i.e. the indent created by the list style and vertically aligned with paragraph text (so that it looks like being part of the first line). The number is echoed through a cross-reference field to a numbered paragraph. “:” is manually added.

The frame covers the real list item number and its background hides the real number.

When you edit your text, the cross-references update as expected. You still have a little annoyance: if you copy and paste a list item, the frames are not copied with the text. You must manually copy them one by one and perhaps restyle them by applying any frame style, then again the intended frame style. F9 will fix numbering order.