Millisecond Forums

If you want to build a drag & drop mechanic, study the "Tower of London" script available from the Task Library. Be warned: This isn't trivial.If you want to go with the "assign numbers" option, consider using <surveypage>s with a bunch of <caption>s, <textbox>es, <dropdown>s plus validation logic. See e.g. http://www.millisecond.com/forums/FindPost7561.aspx & https://www.millisecond.com/forums/FindPost7524.aspx

Thanks Dave,

I don't understand the question, I'm afraid.The scripts I referred you to enforce that every available rank (1,2,3 and 4 in the examples) is assigned *exactly once*.

Yes and let's say that we want to force participants to choose only two of four (e.g. 1 & 2 or 1 & 3 but no 1 & 1 nor 1, 4, & 3).In that case I can't use your script directly because in it participant have to "use" every answer exactly once. I need to change it to let participants to choose only two of four answers (no matter which) and not to repeat the answer chosen before.

Yes, understood. Thanks for the clarification. Should be doable. However, here's what I don't "get": If you are ranking 2 out of 4 elements, you only have *two ranks* to assign (1 and 2). What sense does it make to allow for something like 1 and 3? Obviously, there *is* an element in this case with *implicit* rank 2 -- otherwise you would not have been able to assign rank 3 to another element.

Now I understand what you don't :)It's because I reversed "roles" in your script, because of my English limitation it would be easier to clarify it on the example; let's say we have four things (apple, orange, strawberry, apricot) and instruction says "Choose two most liked and rank that two", I'm not interested in the two less liked.
In order to do that I prepared two"dropdown" elements, first says "The most liked fruit" and the second "The second most liked fruit" and in options I have four fruits. My intention is to let participants choose one as "most liked", another one as "second" and to leave the rest unranked. As you see there is the reversion - what was the options in original script (Most liked, Second...) is the content of the "question" here and vice versa.That's exactly my situation (but 20 sentences and participants need to rank 10 most important).

Well, the original (assign rank to object) would be much easier (and thus preferable) to implement than the reverse (assign object to rank).

For the sake of completeness, though, if you absolutely *must* go down the other route, something along the lines of<values>
/ rankstring = ""
/ validranking = false
</values>

<block myblock>
/ trials = [1=mypage]
</block>

<text debug>
/ items = ("<%values.rankstring%>")
/ position = (50%, 5%)
</text>

<surveypage mypage>
/ stimulusframes = [1=debug]
/ questions = [1=r01; 2=r02]
/ ontrialbegin = [values.rankstring=""]
/ ontrialend = [values.rankstring=concat(concat(values.rankstring,dropdown.r01.response),dropdown.r02.response)]
/ ontrialend = [if (
    length(values.rankstring) == 2 &&
    length(replaceall(values.rankstring, dropdown.r01.response, "")) == 1 &&
    length(replaceall(values.rankstring, dropdown.r02.response, "")) == 1
    ) values.validranking = true else values.validranking = false]
/ branch = [if ( values.validranking == false) surveypage.mypage]
</surveypage>

<dropdown r01>
/ caption = "Rank 1"
/ options = ("Object A", "Object B", "Object C", "Object D")
/ optionvalues = ("A", "B", "C", "D")
/ required = true
</dropdown>

<dropdown r02>
/ caption = "Rank 2"
/ options = ("Object A", "Object B", "Object C", "Object D")
/ optionvalues = ("A", "B", "C", "D")
/ required = true
</dropdown>
should be workable.

Thank you,