SUBSTRING check

[Ivy]

Hi,

I have two variable a  & b, I would like to check whether b string is in a string .  

index(a, b )  could not pick up some values, for examples:

data _null_ ; 

a = "Bevacizumab,Cisplatin,Pemetrexed Disodium" ;

b = "Bevacizumab,Pemetrexed Disodium" ;

c = index( a, b ) ;

put c  ;

run ;

Should I need to seperate the B string and then use index function or whether there is another function to check this ?

Thank you !

[Reeza]

You'll have to separate the strings. 

The INDEX() function looks for an exact match, not for each of the words. 

You can try PRX functions or put the words into a temporary array and use that. 

It depends on how generalized your problem is, is the B changing per row, or fixed across the data set?

[Ivy]

Thank you, Reeza .

B is changing per row, some B string has one part, some has two or three parts. Maybe I need to separate them. Thank you again !

[Reeza]

Yes, you need to separate them. Use the scan function.

If you make the data long, you can change it to a SQL query which should be easier to code as well.

[stat_sas]

data want(drop=search_string i flag);
set have;
flag=0;
length search_string $30;

do i=1 to countw(b,',');
    do search_string = scan(b,i,','); 
       if index(trim(a), trim(search_string)) then flag+1;
    end;
end;

if flag=countw(b,',') then found='b in a';
else found='b not in a';

run;

[PGStats]

You couild always use regular expressions

data _null_; 
length pat $60;
a = "Bevacizumab,Cisplatin,Pemetrexed Disodium" ;
x = "Bevacizumab,Cisplatin,Pemetrexed Dissodium" ;
b = "Bevacizumab,Pemetrexed Disodium";
pat = prxchange("s/,/.*/", -1, b);
pat = cats("/", pat, "/i");
c = prxmatch(pat, a) > 0;
put c=;
d = prxmatch(pat, x) > 0;
put d=;
run ;

Will match if the substrings are in the same order.