Re: st: Automating graphs with data-dependent reference lines and saving with meaningful names.

[Oliver Jones <ojones@wiwi.uni-bielefeld.de>]

Am 26.05.2011 14:27, schrieb Maclennan, Graeme S.:
> Dear Statlist, I have a tricky (at least to me) problem which I am currently unable to solve.  I have P persons that answer Q Likert style questions on a scale of 1 to 9.  What I need is plot of the distribution of responses to each question, but for each person P I want to indicate (using a line say) on the graph their response. This is to be fedback at a later stage, so I want to save each graph with a useful name that indicates the P and Q.   So in "pseudo code":
>
> For each qestion Qj
>          For each person Pi
>                  Histrogram Qj, discrete add line at  value of Pi response to Qj, Save graph with name PiQj
>
>
>
> Problem 1 is getting the line to be different for each person P, in the archives I found that -addplot- with -pci- gives me what I want, but I cannot work out to automate the reading of the x-value. For example in the baby dataset below
>
> ******** Example Dataset************
> clear
> set obs 20
> set seed 1234
> gen p = _n
> forvalues j = 1/5{
>          gen q`j' = 1 + int(9*uniform())
> }
>
> hist q, discrete addplot(pci 0 5 20 5 , legend(off)) percent
> ***************End********************
>
> P1 answered 5 to Q1, but is it possible to tell Stata to read the value automatically?

Hi,

First: Your code above didn't work perfectly. One gets an error with the
hist q, because q is an ambigous abbreviation.

Second: Yes you can tell Stata look up the value of q1 for person p == 1.

local answer_q1 = q1[1]
hist q1, discrete addplot(pci 0 `answer_q1' 20 `answer_q1' , legend(off)) percent

If you want you can create locals for all answers and all people by looping, i.e.

count
forval person = 1/`r(N)'{
	forval i = 1/5 {
		local answer_p`person'_q`i' = q`i'[`person']
	}
}

Hope this helps a little bit.
Oliver


> Problem 2 is getting trying to loop over each question for each person and save the graphs.  In reality I wont have nice IDs for P, I have been trying to combine -foreach- over Q and levels of P but I know I am wrong.
> Plus I need to incorporate the solution to above Problem 1 into the loop.  Ignoring that I have been trying variations of the below, but I am out of my depth.
>
> ******** Attempt**********
> levelsof p, local(pi)
> foreach q in q1-q4{
>          foreach i of local pi{
>                  hist q, discrete addplot(pci 0 5 20 5 , legend(off)) percent saving(`q'`p')    /// In here I need to somehow incorprate solution to Problem 1.
>          }
> }
> **********End Attempt******
>
> Any pointing in the right direction is appreciated.
> Regards,
> Graeme MacLennan
>
>
>
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>
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