'is not a valid command' error when using forval

[John Ash]

Hi,
I'm using the following forval command from: How do I create variables summarizing for each individual properties of the other members of a group? Stata FAQ

summarize PERSONID, meanonly
forval i = 1 / `r(max)' { 
      replace ischild = (RO9 == `i') | (RO10 == `i')
      qui by IDHH (ischild), sort:
      replace ownchild =
      cond(RO10[_N] == `i', mchild[_N], fchild[_N])
      if PERSONID == `i' & ischild[_N] 
}

The error I get is 'is not a valid command' on the line 'qui by IDHH (ischild), sort:'
Does someone know what's wrong? I'm new to Stata and have never dealt with forval before. I am writing this code straight into the state command window and not a do file.

Thanks in advance

[Justin Niakamal]

My guess is

& ischild[_N]

should be

& ischild == ischild[_N]

[Nick Cox]

 qui by IDHH (ischild), sort: replace ownchild = cond(RO10[_N] == `i', mchild[_N], fchild[_N]) if PERSONID == `i' & ischild[_N]   

is all one (horrendous) command. The FAQ https://www.stata.com/support/faqs/d...ng-properties/ uses #delimit ; to indicate that the command line you are modifying doesn't end before the semi-colon.

[Sven-Kristjan Bormann]

You omitted the commands

#delimit ;
...
;

from your code. If you don't run your code from a do-file, then the code looks like this

summarize PERSONID, meanonly
forval i = 1 / `r(max)' { 
      replace ischild = (RO9 == `i') | (RO10 == `i')
      qui by IDHH (ischild), sort: replace ownchild = cond(RO10[_N] == `i', mchild[_N], fchild[_N]) if PERSONID == `i' & ischild[_N] 
}

[John Ash]

Thanks for the reply - I tried the suggestion but it still doesn't work.
Let me post my entire original code:

by IDHH RO9, sort: gen fchild = _N if RO9 < .
by IDHH RO10, sort: gen mchild = _N if RO10 < .  
 gen byte ownchild = 0  
 gen byte ischild = 0  summarize PERSONID, nomeanonly    
 forval i = 1 / `r(max)' {   
           replace ischild = (RO9 == `i') | (RO10 == `i')  
           qui by IDHH (ischild), sort:  
           replace ownchild =  
           cond(RO10[_N] == `i', mchild[_N], fchild[_N])  
           if PERSONID == `i' & ischild[_N]  
 }

[John Ash]

You omitted the commands

#delimit ;
...
;

from your code. If you don't run your code from a do-file, then the code looks like this

summarize PERSONID, meanonly
forval i = 1 / `r(max)' {
replace ischild = (RO9 == `i') | (RO10 == `i')
qui by IDHH (ischild), sort: replace ownchild = cond(RO10[_N] == `i', mchild[_N], fchild[_N]) if PERSONID == `i' & ischild[_N]
}

Amazing - thanks a lot. When I used the delimit it gave an error - but I guess that only works in a do file. I didn't know much about do files and it didn't mention it in the FAQ so was a bit confused. Thanks again!!