creating a new variable based on a frequency

[c_starfish]

Hello, 

I am dealing with data where I have subject IDs and a variable that tells me the diseases each subject has. Some of the subjects have more than one disease but they are just inputted in the dataset multiple times. For example: 

data example;

input ID condition$ ;

datalines; 

45 diabetes

46 cancer

46 diabetes 

47 cancer 

; 

What I want is a summary of the frequency of conditions. For example, X number of people have only one condition but Y number of people have two conditions and Z number of people have three conditions, etc. I am thinking that I would just like to create a variable that tells me the number of conditions each participant has but I am not sure how to do this. 

Is there a way I can do this? 

[Reeza]

Is a patient going to have multiple diagnosis entries for the same event, ie will diabetes be there twice?

If not, you can use a PROC FREQ to get the number of counts. Otherwise, you're looking to count distinct. 

I just posted a solution on how to count distinct items per group here:

https://communities.sas.com/t5/SAS-Statistical-Procedures/Count-unique-variables-associated-with-one...

[error_prone · Accepted solution]

Use proc summary to get the number of conditions each patient has, then pro freq to get the required output.

proc summary data=example nway;
   class id;
   output out=CondById(drop=_type_ rename=(_freq_=NumConditions));
run;


proc freq data=CondById noprint;
   tables NumConditions / out=FreqCond(drop=percent);
run;

[c_starfish]

Hey thank you so much! what an easy solution to my problem. You rock!