topic Re: Not able to find out the reasoning behind this. Please Help in SAS Programming

Not able to find out the reasoning behind this. Please Help

Saugata — Fri, 03 May 2013 06:11:54 GMT

HI All,

Please find the below code:

Data xx;

Var2='Lorem ipsum dolor';

Position=Find(%Substr(Var2,1,16),' ',-15);

%Let position2=%sysfunc(Find(%Substr(Var2,1,16),' ',-15));

Run;

%PUt &Position2.;

Now if you run the code you will find that Position and Position2 are having different values in them (Position =12 and Position2=0), but they both should produce the same result.

I can find that once you include %sysfunc before Find function it starts to give you 0 as output. Once %sysfunc is out of the equation everything is fine.

But I need to use this %sysfunc in %Let statement (need to create a Macro variable which will be used in this dataset itself. So, call symput is out of the question.) and I can not find a different way.

Most importantly I want to know why SAS is doing this? Please help.

Thnaks in advance for your efforts.

Regards,

Saugata Mukherjee.

Re: Not able to find out the reasoning behind this. Please Help

data_null__ — Fri, 03 May 2013 10:22:49 GMT

I cannot find the reasoning behind your question.

17         Data _null_;;
18            Var2='Lorem ipsum dolor'; 
19            Position=Find(var2,' ',-15);
20            put (_all_)(=);
21           Run;

Var2=Lorem ipsum dolor Position=12
NOTE: DATA statement used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds
      

22         %let var2=Lorem ipsum dolor;
23         %Let position2=%sysfunc(Find(&Var2,%str( ),-15));
24         %PUT &=Position2.; 
POSITION2=12
25         

Re: Not able to find out the reasoning behind this. Please Help

Saugata — Fri, 03 May 2013 11:20:08 GMT

Hi,

Thanks a lot for your reply. But the problem comes when we add an additional substring function. Please try the below code:

%let var2=Lorem ipsum dolor;

%Let position2=%sysfunc(Find(%Substr(Var2,1,16),%str( ),-15));

%PUT &Position2.;

The log is:

407 %let var2=Lorem ipsum dolor;

408 %Let position2=%sysfunc(Find(%Substr(Var2,1,16),%str( ),-15));

WARNING: Argument 3 to macro function %SUBSTR is out of range.

409 %PUT &Position2.;

SYMBOLGEN: Macro variable POSITION2 resolves to 0

Where as the string is clearly more than 16 character long.

Please help me.

Regards,

Saugata Mukherjee.

Re: Not able to find out the reasoning behind this. Please Help

data_null__ — Fri, 03 May 2013 11:22:30 GMT

Maybe you need to put an ampersand in from of the variable VAR2.

Why do you need %SUBSTR?

Re: Not able to find out the reasoning behind this. Please Help

Saugata — Fri, 03 May 2013 12:23:45 GMT

Yes, I am sorry I should have used ampersand in this particular case.

But I am just curious, why can't we use a variable in this statement. What I want to as is, why the below code is producing 0 as output:

Data xx;

Var2='Lorem ipsum dolor';

%Let position2=%sysfunc(Find(%Substr(Var2,1,16),%str( ),-15));

Run;

%PUt &Position2.;

Is it because SAS is considering Var2 as a string instead of a variable?

And I need substr because I want to cut the Var2 variable in two variables, each should not have more than 16 characters (Hence %substr)and no word should be cut off in between (hence finding the last space before 16th character).

The whole code is not here. Once I figure out the position of last space before 16th character, it will be pretty easy.

So, please help me to fix this, as making Var2 a Macro variable will be a cumbersome process in my situation.

Regards,

Saugata Mukherjee.

Re: Not able to find out the reasoning behind this. Please Help

data_null__ — Fri, 03 May 2013 12:30:19 GMT

It looks like you don't know the difference between macro and data step. You will need to consult the documentation and get a better understanding of when to use macro and the timing wrt data step execution.

Having said that I don't think you need to use macro AT ALL.

I would work with data step using find and and substr and then if you must use macro convert it to use %SYSFUNC. etc.

Re: Not able to find out the reasoning behind this. Please Help

Saugata — Fri, 03 May 2013 12:40:25 GMT

Thanks for opening my eyes I was using structure from a old code and in doing so I completely overlooked that I do not need to create a macro variable, instead dropping the postion variable would be enough. Now it is working perfectly.

I guess sometimes you miss out small things

Thanks again for your help.