Although I would also recommend DO IF/ELSE IF/END IF rather than a series of IF statements (even though the IF statements require fewer lines of code), I don't think it makes any difference in processing time as long as there are no intervening EXECUTE commands.

For example:

if (x=1) y=3. if (x=2) y=4. execute.

and

do if (x=1). compute y=3. else if (x=2). compute y=4. end if. execute.

will, I think, take the same amount of processing time, since in both cases the data file is only read once.

-----Original Message----- From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU]On Behalf Of John Dashper Sent: Friday, August 27, 2004 10:08 AM To: SPSSX-L@LISTSERV.UGA.EDU Subject: Re: Compute using multiple IFs

Much better with Do If.Only one pass of the file.

String special (A30).

do if(q7a_1>0). compute special = table1e. else if(q7b_1>0). compute special = table2e . else if(q7c_1>0). compute special = table3e .

etc

end if. exe.

OK?

John Dashper

> -----Original Message----- > From: Nico Peruzzi, Ph.D. [mailto:nperuzzi@yahoo.com] > Sent: 27 August 2004 16:08 > To: SPSSX-L@LISTSERV.UGA.EDU > Subject: Compute using multiple IFs > > Hi Listers, > > I am trying to compute a new variable (let's call it > "special") that does the following: > > -it equals the value in a variable called "table1e" if > variable "q7a_1" > 0 > -it equals the value in "table2e" if variable "q7b_1" > 0 > -equals value in table3e if q7c_1 >0 > etc. > > the q7 variable series variables are mutually exclusive, > and they occur in a specific order (i.e., q7a_1 would be > the first one to check for a value, then q7b, etc.) > > When I pasted out of the GUI, doing one if statement, I got > the following: > > IF (q7a_1>0) special = table1e . > EXECUTE . > > Would I just string a few of these statements together? > > IF (q7a_1>0) special = table1e . > IF (q7b_1>0) special = table2e . > IF (q7c_1>0) special = table3e . > etc > EXECUTE . > > Thanks in advance for any tips, > > Nico