RE: st: Check if variable names are equal for program flow

[Joe Canner <jcanner1@jhmi.edu>]

Eric,

Try:

. if "`svyitem'" == "smokwholage18_2cat" {...}

Your code is comparing the actual values of the variables rather than the variable names.

Also, for clarity you might be able to get rid of the local macro and just do:

. foreach svyitem of varlist cig_init smokever_initiation smokwholcig smokwholage18_2cat smokwholage18_24 {...}

Regards,
Joe Canner
Johns Hopkins University School of Medicine

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Eric Canen
Sent: Tuesday, September 10, 2013 1:46 PM
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: Check if variable names are equal for program flow

I realized that my first block of code had an unclosed bracket it should read:

local cig_init smokever_initiation smokwholcig smokwholage18_2cat smokwholage18_24

foreach svyitem in `cig_init' {

//do some stuff for every variable
//added the next command to check what the if is evaluating to
display `svyitem' == smokwholage18_2cat
if `svyitem' == smokwholage18_2cat{
//do some extra stuff on smokwholage18_2cat
}
}


----- Original Message -----
From: Eric Canen <clockgoesby@yahoo.com>
To: "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Cc: 
Sent: Tuesday, September 10, 2013 11:31 AM
Subject: st: Check if variable names are equal for program flow

I want to loop over a set of variables using a local macro. There is a variable in the set where I want to do additional 
procedures when it comes up in the loop, so I added an if statement that is meant to compare whether or not
the current variable is the one that has additional procedures. The problem is that the if statement is not evaluating
as I expected. Its evaluating as true even when as far as I can tell it should be false. Here is the code:

local cig_init smokever_initiation smokwholcig smokwholage18_2cat smokwholage18_24

foreach svyitem in `cig_init' {

//do some stuff for every variable
//added the next command to check what the if is evaluating to
display `svyitem' == smokwholage18_2cat
if `svyitem' == smokwholage18_2cat{
//do some extra stuff on smokwholage18_2cat
{
}

The first variable in the loop (smoker_initiation) works fine. The debugging code using the display command prints a "0" like I expected.
The second variable (smokwholcig) seems to have a problem. The debugging code prints a "1" and so it is evaluating to true when 
as far as I can tell it should be evaluating to a "0" because as far as I can tell smokwholcig == smokwholage18_2cat is false.

I also tried evaluating the variable names as strings and it just concatenates them together. Specifically I ran:


. display "`svyitem'" == "smokwholage18_2cat" 

smokwholcigsmokwholage18_2cat


It just concatenated the two strings together.

I have run the frequencies on both variables and they are different from one another though because of skip patterns in the survey
the cross tabulation does yield a reduced table (see below). That is part of the reason I want to use the if statement to control
what is done for smokwholage18_2cat. Here is the output of the cross tabulation between the two variables:

. tabulate smokwholcig smokwholage18_2cat

  Have you |

      ever | How old were you when you smoked
  smoked a | a whole cigarette for the first
     whole |         time before 18?
cigarette? |         1          2        997 |     Total
-----------+---------------------------------+----------
         1 |       118        139          7 |       264 
-----------+---------------------------------+----------
     Total |       118        139          7 |       264 

Can anyone help me figure out why this if statement is working the way it is and what I can do to fix it?

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