Get the different chars appearance frequency

options formdlim='-';

************* Another Problem form MITBBS *****************;

* The question like this: have data x like below consists of 1 and 2 only *;

* Want to count the frequency of 1's and 2's appear consecutively *;

* More detailed, how many times 1 appear once consecutively *;

* More detailed, how many times 1 appear twice consecutively *;

* And so on *;

* Until how many times 2 appear ** times consecutively ? *;

* That is, the result should be: *;

/**************************************************************

                         x   counter      freq

                      ----------------------------

                         1         1         3

                         1         4         1

                         2         2         2

                         2         3         1

                         2         5         1

**************************************************************/

data test;

  input x;

  cards;

  1

  2

  2

  1

  1

  1

  1

  2

  2

  2

  2

  2

  1

  2

  2

  1

  2

  2

  2

  ;

run;

data new;

   set test;

   by x notsorted;

   retain counter;

   if first.x then counter=0;

      counter+1;

   if last.x then output;

run;

proc print data=new;

run;

proc sql;

   select x, counter, n(counter) as freq

   from new

   group by x, counter

   order by x, counter

   ;

quit;

***  If don't use proc sql, we can use these data steps: **;

data new;

   set test;

   by x notsorted;

   retain counter;

   if first.x then counter=0;

      counter+1;

   if last.x then output;

run;

proc print data=new;

run;

proc sort data=new;

  by x  counter;

run;

data want;

  set new;

  by x  counter;

  retain freq;

  if first.x  or first.counter then  freq=1;

    else freq=freq+1;

  if last.x or last.counter then output;

run;

proc print data=want;

run;