Correction : st: Need help understanding stata graphics from http://www.survey-design.com.au/Stata%20Graphs.html.

[Michael Stewart <michaelstewartresearch@gmail.com>]

Hello ,


I am trying to learn stata graphics from the webpage
http://www.survey-design.com.au/Stata%20Graphs.html.
I couldn't understand  few graphs and was hoping if
senior/experienced programmers would help me understand them


QUESTION:


*****************example start ******************************

histogram - add x bar labels for the centre of each bar

sysuse auto, clear
twoway__histogram_gen mpg  , bin(6) generate(h x , replace )
count if !missing(x)
forvalues i=1/`=r(N)' {
  local label `label'  `=string(x[`i'],"%8.2f")'

}

histogram mpg , bin(6) xlabel(`label')

*****************example end ******************************

I cant understand stata commands after "count if !missing(x)"

1)What is the utility of the forach loop
2)what does the notation   i=1/`=r(N)' mean ; typically I  see macros
like `r(N)'
3)How does local label `label'  `=string(x[`i'],"%8.2f")' work?

Thanks a lot for your time and consideration.
--
Thank you ,
Yours Sincerely,
Mike.








On Mon, Jul 8, 2013 at 8:38 AM, Michael Stewart
<michaelstewartresearch@gmail.com> wrote:
> Hello ,
>
>
> I am trying to learn stata graphics from the webpage
> http://www.survey-design.com.au/Stata%20Graphs.html.
> I couldn't understand  few graphs and was hoping if
> senior/experienced programmers would help me understand them
>
>
> QUESTION:
>
>
> *****************example start ******************************
>
> histogram - add x bar labels for the centre of each bar
>
> sysuse auto, clear
> twoway__histogram_gen mpg  , bin(6) generate(h x , replace )
> count if !missing(x)
> forvalues i=1/`=r(N)' {
>   local label `label'  `=string(x[`i'],"%8.2f")'
>
> }
>
> histogram mpg , bin(6) xlabel(`label')
>
> *****************example end ******************************
>
> I cant understand stata commands after "count if !missing(x)"
>
> 1)What is the utility of the forach loop
> 2)what does the notation   i=1/`=r(N)' mean ; typically I  see macros
> like `r(N)'
> 3)How does local label `label'  `=string(x[`i'],"%8.2f")' work?
>
> Thanks a lot for your time and consideration.
> --
> Thank you ,
> Yours Sincerely,
> Mike.
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/faqs/resources/statalist-faq/
> *   http://www.ats.ucla.edu/stat/stata/



--
Thank you ,
Yours Sincerely,
Mike.
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/