reverse strings

[BrahmanandaRao]

data nnn;
set sashelp.class;
length rev_string $ 25;
do i=1 to length(rev_string);
rev_string=substr(Name,length(Name)-i,1);
end;drop i ;
proc print;run;

how reverse string (Name) where i did wrong in the class dataset

[PeterClemmensen]

Is this an assignment? Otherwise, why not use the Reverse Function?

[BrahmanandaRao]

Yes Peter 

 I am trying instead of REVERSE function

[PaigeMiller]

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@BrahmanandaRao wrote:

Yes Peter 

 I am trying instead of REVERSE function

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Why write your own code instead of the REVERSE function?

[ger15xxhcker]

The DO loop you wrote is incorrect. To reverse a string, you can use the SAS function REVERSE(). You can use it, like this:
rev_string = reverse(Name);

[Astounding]

Your DO loop replaces REV_STRING with a single character each time through the loop ... not what is needed.  Do you need help in fixing that?

What about blanks?  For example, this code contains 7 trailing blanks in STRING:

length string $ 10;
string = 'ABC';
rev_string = reverse(string);

Using the REVERSE function, the result would contain 7 leading blanks followed by "CBA".  Are you attempting to replicate that result, or are you intending to ignore the blanks and get "CBA" followed by 7 trailing blanks?

[PaigeMiller]

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@Astounding wrote:

Your DO loop replaces REV_STRING with a single character each time through the loop ... not what is needed.  Do you need help in fixing that?

What about blanks?  For example, this code contains 7 trailing blanks in STRING:

length string $ 10;
string = 'ABC';
rev_string = reverse(string);

Using the REVERSE function, the result would contain 7 leading blanks followed by "CBA".  Are you attempting to replicate that result, or are you intending to ignore the blanks and get "CBA" followed by 7 trailing blanks?

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Either of the "problems" caused by spaces in the REVERSE function are easy to fix. Easier than writing your own code.

[Astounding]

You're absolutely right, the REVERSE function would be easier and more accurate. I'm assuming that this is a homework assignment and the instructor is trying to make that exact point: functions are thoroughly tested and debugged and easier to use when compared to "do it yourself" code.

[Kurt_Bremser]

Use two index variables: one to count down from length(name) to 1, the other starting at 1 and incrementing in the loop. Then use SUBSTR on the left and right side of the assignment (left for rev_string, right for name).

[PeterClemmensen]

Also, an opportunity to use the rarely used character format $REVERS Format .