List Shifter: Reverse, Rotate, Swap and ITERATE (Loop) Over Bubble Lists | Now Part of Floppy

[keith]

Hey @rico.trevisan, yeah List Shifter’s SORT action lets you sort one list (the list held in List Shifter’s Original List) by some other arbitrary list (the “Sort By List”). As long as you can construct the Sort By list in such a way that the item at each index corresponds to the item at that same index in the Original List, this will work.

So, in your case you have a list of Teams:

1. Team 1
2. Team 2
3. Team 3

And then you have an expression (or have constructed, using Process List for example) a corresponding list of Maturity scores (where I’ve also supposed a value) like so:

1. Maturity Score associated with Team 1 (25)
2. Maturity Score associated with Team 2 (100)
3. Maturity Score associated Team 3 (50)

When you execute that SORT action (sorting as number, descending), List Shifter’s Shifted List would contain:

1. Team 2
2. Team 3
3. Team 1

Now, one weakness of the SORT action in List Shifter is that the sorted “Sort By” list is not published. This would have been handy in some cases, but I was tired of adding new outputs to List Shifter. Typically this isn’t an issue, as often SORT is used just for visually organizing a list in a Repeating Group (as you are doing) and typically the “sort by” list values will be visualized there as the result of some scalar expression within the cell.

In my example, the sorted Maturity values would be [100, 50, 25]. And if you needed that list you’d just take whatever expression you used for the Sort By list and do :sorted (by value descending) on it.

(Aside: There’s a similar action in Floppy - Count Fields/Sort - that can also do the same thing although the sort type is strictly numeric, but it does publish the sorted list of numbers.)

Internally how this works is we create an array of objects where each object is like:

{ original_list_value: Team 1, sort_by_value: 25 }

And then we sort that array of objects by the value parameter and then extract the original_list_values, which are now sorted and those are published to List Shifter’s Shifted List.

Does this help?

The tricky part oftentimes is the construction of that “Sort By” list which you might need to construct using a PROCESS List action (and possibly a second list shifter) and its associated “SET Process FIELD of Interest” action. For an example (not exactly parallel to what you are doing, but that is constructing a list of counts of some associated thing), see:

Sorting a RG based on :count list of dates

The feature you’re using here (n your screenshot) is not “sort by”, it’s “change the field we should look at to sort by”. Consult the reference for details on how that works, but I don’t think that is what you are trying to do. (I’m mobile at the moment.) The Sort field in the Search configuration dialog will only let you select a field that exists on the Thing you are searching. You can also add :sorted by after the fact. But again, you can’t take some arbitrary list and and use that as a sor…

(and then there’s a bunch of intervening stuff where I create the scenario, but then the punchline is in the following reply)

Sorting a RG based on :count list of dates

OK, so what about the list of Concert Dates? Is that truly just a vector? Let’s check: [image] Here are the expressions we are checking… And here is how it looks in run mode: Looks like I was wrong about collapsing duplicates on :count… Full transparency: [image] There are still duplicate values in our list… … however, the point remains the same: :count on this expression does not yield a LIST OF COUNTS, but just a scalar value… 47. And, more importantly, you see that what…

And then here:

Sorting a RG based on :count list of dates

Now that @despega replied more, I can reply more (seem to have hit a spam-filter… you can only reply so many times in a thread, apparently). Our next step is to use SET Process FIELD of Interest for our List Shifter. We need to get at the values for “Concert Dates”. By setting this as our “Field of Interest” we can access those values in the PROCESS List action: [image] Now for our PROCESS List step: What we will do is take each item in the “Original List” (this is the list of Concert Goers)…

The type of scenario described above is quite common, which is why I created the “Count Fields/Sort” action in Floppy (which makes it super easy to get a list of counts and then sort by them). However, in your case you might need to iterate over your Teams and Assessments lists to match each team with its associated Assessment’s Maturity score (though perhaps there is a native Bubble expression that gives you that).