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st: series of value labels and collapse


From   akonseig@uni-bonn.de
To   statalist@hsphsun2.harvard.edu
Subject   st: series of value labels and collapse
Date   Mon, 07 Jul 2003 16:19:20 +0200 (MES)

Dear Statalisters,
I am having trouble with a programme I wrote for specific data management 
purpose. I have 271 farmers who may combine at most 3 types of crop c1 c2 c3. 
The data is in long format and therefore ci records in column the type of 
crop per plot owned by the farmer and in row ci show the mixture of crop by 
the farmer in each of the plot. A lot of missing values appear of course in 
the data.
My first objective was therefore to create dummies ci_di per crop (maximum of 
46 types of crop) and this is done through the first section of my do file 
below but in my attempt to pass a label value that identify each type of crop 
I got the error : label beans already defined
r(110);
I actually used some resources of Statalist (posted by Nick but on different 
issues) to automate the labelling.
The next section of the do file simply collapse by crop type to get the mean 
value of area croped. Here also I got more than hundred data files. Do I have 
to go through each file to display the output of interest (mean value of area 
croped) or is there any way I can gather these results all together?
During the survey the farmer could not know the portion of land allocated to 
each crop and one methodological question is to know if it is a good idea to 
simply divide the total land by the number of crops cultivated on the plot.
I would appreciate any help from the list.
Best regards.
Adama

*--------STEP1: tab, generating dummies per crop and labelling their values-
version 7.0
use ctypes, clear
program define compo
foreach var of local 0{ 
sort id
tab `var', gen(`var'_d)

*below the local cropnames is a sample of the 46 types of crops I have. and 
*at the end of the program I pasted the error generated		

local cropnames "beans	cassava maize rice watermelon macaxeira  maxixe melon 
raizman tomato jambu goma cucumber Cheiroverde sweetpotato tabaco Jerimum 
PimentaCheiro Pimenta Doce Beringela"

local codes "beans cassava maize rice watermelon macaxeira  maxixe melon 
raizman tomato jambu goma cucumber Cheiroverde sweetpotato tabaco Jerimum 
PimentaCheiro Pimenta Doce Beringela"

local i = 1
foreach x of local cropnames {
        local y : word `i' of `codes'
        lab define `x' 1 "`y'" 0 "no"
	  capture forvalues j=1/46{
	  label val `var'_d`j' `x'
	  sum  area if  `var'_d`j'==1
	  }
	  local i = `i' + 1
}
end
local area "c1 c2  c3"
foreach k of local area {
 compo `k'
 } 
program drop compo
exit
label beans already defined
r(110);

*------------------STEP 2: mean value of the area croped by crop type. 
*Everything works fine but how to put together the outputs generated by 
*collapse--------------------------

version 7.0
program define compo2
foreach var of local 0 {
	use ctypes, clear
	sort id
	foreach v of var * {
	local l`v' : variable label `v'
      if `"`l`v''"' == "" {
	local l`v' "`v'"
 	}
      }
	preserve
	capture forvalues i = 1/46  {
      use ctypes, clear
      collapse area if  `var'_d`i'==1
	foreach v of var * {
	label var `v' "mean value of `l`v'' `var'_d`i'"
	}
	keep  id plot area fareacrop
	save f`var'`i', replace
	}
	restore
}
end
local area "c1 c2 c3"
foreach j of local area {
 compo2 `j'
 } 
program drop compo2
exit



 

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