topic Re: SUBSTRN in SAS Programming

SUBSTRN

GingerJJ — Tue, 31 Aug 2021 20:09:20 GMT

I have

x=abcdefg

y= SUBSTRN(x,-1,3);

It returns me abc. but I want efg.

Thank you!

Re: SUBSTRN

ballardw — Tue, 31 Aug 2021 20:37:15 GMT

@GingerJJ wrote:

I have

x=abcdefg

y= SUBSTRN(x,-1,3);

It returns me abc. but I want efg.

Thank you!

The real question is do you want the last three characters, regardless of length, or do you want the substring that starts in the 5th position to the end of the value, or some other rule?

The above returns 'abc' because you told it to start in a position before the string and get the following 3 characters.

From the documentation : If the position that you specify is non-positive, the result is truncated at the beginning, so that the first character of the result is the first character of the string.

Position is the second parameter, or where to start

Assuming you want the last 3 characters try

y= SUBSTRN(x,length(x)-2);

Why minus 2 you may ask. The function want a starting position in the second position. If the length of string is 7, then you want positions 5, 6 and 7 (assuming you want three characters). So to get 5 you want 7-2.

Re: SUBSTRN

data_null__ — Tue, 31 Aug 2021 21:15:08 GMT

@GingerJJ wrote:

I have

x=abcdefg

y= SUBSTRN(x,-1,3);

It returns me abc. but I want efg.

Thank you!

-1,3 does not return abc

53         data _null_;
54            x='abcdefg';
55            do i = -1 to 8;
56               y=SUBSTRN(x,i,3);
57               put i 2. +1 y=$hex10. +1 y=;
58               end;
59            run;

-1 y=6120202020  y=a
 0 y=6162202020  y=ab
 1 y=6162632020  y=abc
 2 y=6263642020  y=bcd
 3 y=6364652020  y=cde
 4 y=6465662020  y=def
 5 y=6566672020  y=efg
 6 y=6667202020  y=fg
 7 y=6720202020  y=g
 8 y=2020202020  y=

Re: SUBSTRN

Tom — Tue, 31 Aug 2021 21:39:55 GMT

Explanation:

If you start in column -1 and want 3 characters then the string you want ends at column 1.

If you start in column S and want L characters then the string ends at column (S+L-1).