Count repeated values

[atobias]

I am interested in generating two variable counting how many times a given value is repeated and how many times it is repeated consecutively.

For example, in the above dataset, I need to count how many times 1 is repeated and repeated consecutively in the variable X, and these countings are placed in the new variables n and rep, respectively.

id X n rep
1 0 0 0
2 1 1 1
3 0 0 0
4 1 2 1
5 0 0 0
6 1 3 2
7 1 3 2
8 0 0 0
9 1 4 2
10 1 4 2

Any ideas or suggestions?
Huge thanks!

[Carlo Lazzaro]

atobias:
do you mean something along the following lines (please note: the code does not consider missing values)?

. g wanted_1=sum(X) if X==1


. replace wanted_1=0 if wanted_1==.


. list

     +-----------------------------+
     | id   X   n   rep   wanted_1 |
     |-----------------------------|
  1. |  1   0   0     0          0 |
  2. |  2   1   1     1          1 |
  3. |  3   0   0     0          0 |
  4. |  4   1   2     1          2 |
  5. |  5   0   0     0          0 |
     |-----------------------------|
  6. |  6   1   3     2          3 |
  7. |  7   1   3     2          4 |
  8. |  8   0   0     0          0 |
  9. |  9   1   4     2          5 |
 10. | 10   1   4     2          6 |
     +-----------------------------+

. egen wanted_2=group(id X) if X[_n]==1 & X[_n+1]==1

. replace wanted_2=0 if wanted_2==.

. list

     +----------------------------------------+
     | id   X   n   rep   wanted_1   wanted_2 |
     |----------------------------------------|
  1. |  1   0   0     0          0          0 |
  2. |  2   1   1     1          1          0 |
  3. |  3   0   0     0          0          0 |
  4. |  4   1   2     1          2          0 |
  5. |  5   0   0     0          0          0 |
     |----------------------------------------|
  6. |  6   1   3     2          3          1 |
  7. |  7   1   3     2          4          0 |
  8. |  8   0   0     0          0          0 |
  9. |  9   1   4     2          5          2 |
 10. | 10   1   4     2          6          0 |
     +----------------------------------------+

.

[Nick Cox]

tsspell from SSC may help.

clear 
input id X n rep
1 0 0 0
2 1 1 1
3 0 0 0
4 1 2 1
5 0 0 0
6 1 3 2
7 1 3 2
8 0 0 0
9 1 4 2
10 1 4 2
end 

tsset id 
tsspell, cond(X == 1)
egen REP = max(_seq), by(_spell)
order id X n _spell rep REP 

list, sepby(_spell)

     +-----------------------------------------------+
     | id   X   n   _spell   rep   REP   _seq   _end |
     |-----------------------------------------------|
  1. |  1   0   0        0     0     0      0      0 |
     |-----------------------------------------------|
  2. |  2   1   1        1     1     1      1      1 |
     |-----------------------------------------------|
  3. |  3   0   0        0     0     0      0      0 |
     |-----------------------------------------------|
  4. |  4   1   2        2     1     1      1      1 |
     |-----------------------------------------------|
  5. |  5   0   0        0     0     0      0      0 |
     |-----------------------------------------------|
  6. |  6   1   3        3     2     2      1      0 |
  7. |  7   1   3        3     2     2      2      1 |
     |-----------------------------------------------|
  8. |  8   0   0        0     0     0      0      0 |
     |-----------------------------------------------|
  9. |  9   1   4        4     2     2      1      0 |
 10. | 10   1   4        4     2     2      2      1 |
     +-----------------------------------------------+