Stata如何剔除每个单元格内重复的字符串

数据如下，我想剔除file列每个单元格内的重复字符串，剔除后的结果应该像result列所示那样，请问有什么方法吗？

1. * Example generated by -dataex-. To install: ssc install dataex
   
2. clear
   
3. input strL(file result)
   
4. "CA294156;CA297738B;CA294156;UB101920C"           "CA294156;CA297738B;UB101920C"
   
5. "CA298876;CA297738B;CA294156;UB451920C;UB451920C" "CA298876;CA297738B;CA294156;UB451920C"
   
6. "CA2865372C;BP20189789;CA2865372C;BP20189789"     "CA2865372C;BP20189789"
   
7. "TY345728N;TY345728N"                             "TY345728N"
   
8. end

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1. * Import raw example data
   
2. cls
   
3. clear
   
4. input strL(file)
   
5. "CA294156;CA297738B;CA294156;UB101920C"           
   
6. "CA298876;CA297738B;CA294156;UB451920C;UB451920C"
   
7. "CA2865372C;BP20189789;CA2865372C;BP20189789"     
   
8. "TY345728N;TY345728N"                             
   
9. end
   
10. 
    
11. list
    
12. 
    
13. *- Split long strings into columns
    
14.         split file, parse(";") gen(unit)
    
15.        
    
16. *- Reshape to long data structure
    
17.         gen i = _n
    
18.         reshape long unit, i(i) j(j)
    
19. 
    
20. *- Drop repeated character units       
    
21.         drop if missing(unit)
    
22.         drop j
    
23.         duplicates drop
    
24.        
    
25. *- Reshape to wide data structure
    
26.         bysort i: gen j = _n
    
27.         reshape wide unit, i(i) j(j)
    
28. 
    
29. *- Add semicolon to each character units
    
30.         foreach v of varlist unit* {       
    
31.                 replace `v' = `v' + ";" if !missing(`v')
    
32.         }
    
33.        
    
34. *- Put all character units together by row and remove the last semicolon
    
35.         egen result = concat(unit*)
    
36.         replace result = substr(result, 1, length(result)-1)
    
37.        
    
38.         keep file result // Get what you want

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我也写一个简单的循环来实现吧，正好熟悉一下continue的使用。

1. split file,parse(";")
   
2. 
   
3. forval i=1/`r(nvars)' {
   
4.         forval j=1/`r(nvars)' {
   
5.                 if `j'<=`i'{
   
6.                         continue
   
7.                 }
   
8.                 replace file`j'="" if file`i'==file`j'
   
9.         }       
   
10. }
    
11. 
    
12. foreach v of varlist file? {
    
13.         replace `v'=`v'+";" if !mi(`v')
    
14. }
    
15. 
    
16. egen result=concat(file?)
    
17. replace result=substr(result,1,strlen(result)-1)

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duplicate drop命令不行吗？

我也来个练练手
split file,p(;)
drop file
sxpose,clear
forvalues i=1/4{
levelsof _var`i', local(mylev) clean
gen  x`i'="`mylev'"
}
keep x1-x4
duplicates drop
sxpose,clear