Change Some Characters Inside Many String Variables

*** This is part of the SPSS Macro tutorials found in page
	http://spsstools.net/macros/learning-macros#ReplacingChrInManyVars
***.


*****************.
*EXAMPLE 1.
*****************.

** Create a data file to work with.
INPUT PROGRAM.
LOOP id=1 TO 3.
VECTOR var(100A8).
LOOP cnt=1 TO 100.
COMPUTE var(cnt)="txt.abc".
END LOOP.
END CASE.
END LOOP.
END FILE.
END INPUT PROGRAM.
EXECUTE.

* The following approach using a loop does NOT work because SUBSTR needs an actual variable name. 
* It does not recognize the vector v(cnt) as a variable name.
VECTOR v=var1 TO var100. 
LOOP cnt=1 TO 100. 
+ LOOP IF INDEX(v(cnt),".")>0. 
+ COMPUTE SUBSTR(v(cnt),INDEX(v(cnt),"."),1)=",". 
+ END LOOP. 
END LOOP. 
EXECUTE. 

* Using DO REPEAT does work. 
DO REPEAT v=var1 TO var100. 
LOOP IF INDEX(v,".")>0. 
+ COMPUTE SUBSTR(v,INDEX(v,"."),1)=",". 
END LOOP. 
END REPEAT. 
EXECUTE. 

* The following macro solution also works. 
* Re-create data file.
INPUT PROGRAM.
LOOP id=1 TO 3.
VECTOR var(100A8).
LOOP cnt=1 TO 100.
COMPUTE var(cnt)="txt.a.bc".
END LOOP.
END CASE.
END LOOP.
END FILE.
END INPUT PROGRAM.
EXECUTE.

SET MPRINT=no. 
*/////////////////////. 
DEFINE !replace (vname=!TOKENS(1)
	/nbvars=!TOKENS(1)
	/oldchar=!TOKENS(1)
	/newchar=!TOKENS(1))
* To replace a character in many string variables.
!DO !cnt=1 !TO !nbvars 
LOOP IF INDEX(!CONCAT(!vname,!cnt),!oldchar)>0.
+ COMPUTE SUBSTR(!CONCAT(!vname,!cnt),INDEX(!CONCAT(!vname,!cnt),!oldchar),1)=!newchar. 
END LOOP. 
!DOEND 
EXECUTE. 
!ENDDEFINE. 
*/////////////////////. 

SET MPRINT=yes. 
* The macro is called as follows.
!replace vname=var nbvars=100 oldchar='.' newchar=','. 


*****************.
*EXAMPLE 2.
*****************.

*Assume variables have unrelated names but are consecutive in the data file 
	(for instance vara, name, address, ..., product are consecutive in the data file).

* The most convenient way to handle this situation is when one has simply to give to a macro 
	the name of the 	first and last variables which have to be processed.
* One of the macro Gems (see "Define list of variables between two variables.SPS" 
	in http://pages.infinit.net/rlevesqu/Macros.htm#MacroGems) can then be used.

* Create a data file.
INPUT PROGRAM.
LOOP id=1 TO 3.
STRING strone text34 str2 beta gamma alpha (A8).
DO REPEAT var=strone text34 str2 beta gamma alpha.
COMPUTE var="txt.ab.c".
END REPEAT PRINT.
END LOOP.
END CASE.
END FILE.
END INPUT PROGRAM.
EXECUTE.
SAVE OUTFILE='c:\temp\testdata.sav'.

* Supppose we want to process variables between text34 and gamma inclusively. This solution assumes we
	have hundreds of variables between these 2 variables. It is not convenient to list them manually. 
* Note however that the following soltuion can also be used when you know that all variables after a given 
	variables need to be processed but you do not know ahead of time the name of the last variable,
	in that case you simply create a new string variable and use that name as the "ending variable".

* Note: when you save the macro Gem in your macro folder, keep ONLY the macro definition, in
	other words, delete the data definition and the example of macro call,
INCLUDE FILE='c:\Program Files\SPSS\macros\DefineListOfVariablesBetweenTwoVariables.SPS'.

* Call the macro Gem to define a macro which gives the list of all variables between the 2 given variables.
!DefList var1=text34 var2=gamma fname='c:\temp\testdata.sav'.

* The macro is called as follows.
SET MPRINT=yes.
!rep_chr oldchar='.' newchar=',' vnames=!list1. 

* See Example 4 below for the definition of the macro !rep_chr.


*****************.
*EXAMPLE 3.
*****************.
*Assume variables have unrelated names; that they are NOT consecutive in the data file; 
	that variables which are between the first and last string variables and do not have to 
	be processed are all NUMERICS.

* The same solution as in EXAMPLE 2 can be used.


* Create a data file.
INPUT PROGRAM.
LOOP id=1 TO 3.
STRING strone text34 str2 beta gamma (A8).
DO REPEAT var=strone text34 str2 beta gamma.
COMPUTE var="txt.ab.c".
END REPEAT PRINT.
END LOOP.
END CASE.
END FILE.
END INPUT PROGRAM.
EXECUTE.
* create a numeric variable between the first and last string variables.
COMPUTE numvar=2.
STRING alpha(A8).
COMPUTE alpha="txt.a.b.c".
SAVE OUTFILE='c:\temp\testdata.sav'.

INCLUDE FILE='c:\Program Files\SPSS\macros\DefineListOfVariablesBetweenTwoVariables.SPS'.

* Call the macro Gem to define a macro which gives the list of all variables between the 2 given variables.
!DefList var1=text34 var2=alpha fname='c:\temp\testdata.sav'.

* The macro is called as follows.
SET MPRINT=yes.
!rep_chr oldchar='.' newchar=',' vnames=!list1. 

* Note that *errors* will occur when the macro attempts to modify the numeric variables (variable numvar), as
	a result of that error, the command will not be executed. We do not care since we did not intend to modify 
	numeric variables in any event.

* See Example 4 below for the definition of the macro !rep_chr.


*****************.
*EXAMPLE 4.
*****************.
* In this case, the names of each string variable which needs to be processed must be explicitely given to the macro.
INPUT PROGRAM.
LOOP id=1 TO 3.
STRING strone text34 str2 alpha (A8).
DO REPEAT var=strone text34 str2 alpha .
COMPUTE var="txt.ab.c".
END REPEAT PRINT.
END LOOP.
END CASE.
END FILE.
END INPUT PROGRAM.
EXECUTE.

* A macro can be used. 
SET MPRINT=no. 
*/////////////////////. 
DEFINE !rep_chr(oldchar=!TOKENS(1) 
	/newchar=!TOKENS(1)
	/vnames=!CMDEND) 
/* To replace a character in many string variables */ 
!DO !vname  !IN  (!vnames) 
LOOP IF INDEX(!vname,!oldchar)>0.
+ COMPUTE SUBSTR(!vname,INDEX(!vname,!oldchar),1)=!newchar. 
END LOOP. 
!DOEND 
EXECUTE. 
!ENDDEFINE. 
*/////////////////////. 


* Assume we want to replace all dots by commas in the last 3 variables.
* The macro is called as follows.
SET MPRINT=yes.
!rep_chr oldchar='.' newchar=',' vnames=text34 str2 alpha .