Re: Re: st: plot yline for different values on each sub plot

[Nick Cox <njcoxstata@gmail.com>]

That's the way that -twoway bar- works. See

SJ-7-1  gr0026  . . . .  Stata tip 42: The overlay problem: Offset for clarity
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. Cui
        Q1/07   SJ 7(1):141--142                                 (no commands)
        tip for graphing several quantities on a continuous axis

Nick

On Tue, Apr 19, 2011 at 10:28 AM, Timothy Colbourn
<t.colbourn@ich.ucl.ac.uk> wrote:
> Thanks Nick,
>
> This method (plotting several twoway graphs at one - some bar and one a line) works well. For those interested my new code is:
>
> twoway (bar livebirth month, barw(0.4)) (bar stillbirth month, barw(0.4)) (bar nnd month, barw(0.4)) ///
>        (bar mvital month, barw(0.4)) (line expbirths month, lcolor(red)), ///
>        ylabel(0(50)350, labsize(small) angle(0)) ytitle("frequency") xlabel(569(2)611, labsize(vsmall) angle(90)) ///
>        xtitle("Month") by(, title("Births and deaths in each RCT arm", size(small)) note("")) ///
>        legend(order(1 "Livebirths" 2 "Stillbirths" 3 "Neonatal Deaths" 4 "Maternal Deaths" 5 "Expected Births") size(vsmall)) by(arm)
>
> The only issue is that instead of the 4 bars for each of the different bar variables (livebirth, stillbirth, nnd and mvital) being plotted beside each other for each month they are plotted on top of each other. Although I think I may remove stillbirth, nnd and mvital from these graphs anyway as they are small numbers, so it is not an issue for me at this time..
>
>
>
>> Date: Fri, 15 Apr 2011 11:57:32 +0100
>> From: Nick Cox <njcoxstata@gmail.com>
>> Subject: Re: st: plot yline for different values on each sub plot
>>
>> I couldn't get the editing approach to work. That just means what it
>> says: I am not at all familiar with all that the Graph Editor can so.
>>
>> This code indicates some technique that might help. Most of it just
>> sets up an example. The key idea is that a different horizontal line
>> can be drawn for a variable that is constant in each panel. It is not
>> a -yline()- and is drawn only over the range of the data.
>>
>> sysuse auto, clear
>> contract foreign rep78, zero
>> graph bar (asis) _freq , over(rep78) by(foreign)
>> egen mean = mean(_freq), by(foreign)
>> twoway bar  _freq rep78, barw(0.5) xla(1/5) || line mean rep78, by(foreign)
>>
>> On Fri, Apr 15, 2011 at 10:16 AM, Nick Cox <njcoxstata@gmail.com> wrote:
>>> I don't know an easy way of doing this. You might try plotting all
>>> four lines in all panels and then deleting three you don't need in the
>>> Editor. Or you might draw each graph separately and then use -graph
>>> combine-. Or you might rewrite using -twoway bar-.
>>>
>>> Either way, your macro manipulation is not going to work as you
>>> intend. Stata interprets your
>>>
>>> `=    '
>>>
>>> stuff precisely once and _before_ the -graph- command gets to work. It
>>> certainly does not do that separately for each separate graph, and it
>>> will always interpret a reference to a variable as a reference to its
>>> value in the first observation.
>>>
>>> Of course, wanting a different yline in each panel is a perfectly
>>> reasonable request, but I think you will need to do it in one of the
>>> ways mentioned above.
>>>
>>> Nick
>>>
>>> On Fri, Apr 15, 2011 at 9:56 AM, Timothy Colbourn
>>> <t.colbourn@ich.ucl.ac.uk> wrote:
>>>
>>>> I have a bar graph plotted 4 times in one for each different arm of the trial I am analysing: by(arm)
>>>>
>>>> I have ploted a yline showing the expected number of births in each arm: yline(`=expbirths') which is a reference against the observed births bars plotted for each month (x axis). The problem is that Stata plots the yline on each of the 4 sub plots at the same value - the value for the first sub plot (arm) - rather than at the value for each arm on each subplot. I have tried yline(`=expbirths by(arm)')  but it does the same thing (with no error message - i.e. it essentially ignores the by(arm). The full syntax for the graph is:
>>>>
>>>> graph bar (asis) livebirth stillbirth nnd mvital, over(month, label( labsize(vsmall) angle(90))) ///
>>>>        ylabel(0(50)550, labsize(small) angle(0)) yline(`=expbirths (arm)') ytitle("frequency") ///
>>>>        by(, title("Births and deaths in each RCT arm", size(small)) note("")) ///
>>>>        legend(order(1 "Livebirths" 2 "Stillbirths" 3 "Neonatal Deaths" 4 "Maternal Deaths") size(vsmall)) by(arm)
>>>>
>>>> Is it possible to plot the yline for each value of expbirths on each subplot?

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