Hi R-helpers,

I have a dataframe as shown below

ID    YEAR_MONTH    ATT_1    ATT_2
1    201301                   Y          1
1    201302                   Y          1
1    201302                   N          0
1    201302                   Y          0
1    201303                   N          1
3    201301                   N          1
3    201302                   N          0
3    201302                   Y          0
3    201302                   Y          1
3    201303                   Y          1

The final dataframe I want should look like

ID    YEAR_MONTH    YEARMONTH_LAG1    ATT1_CHNG  ATT2_CHNG
1      201301                   NA                                   NA
         NA
1      201302                201301                                0
           0
1      201303                201302                                2
           1
3      201301                  NA                                    NA
         NA
3      201302                201301                                0
           0
3      201303                201302                                1
           1

Note:
1. 'YEARMONTH_LAG1 ' is the previous month corresponding to the current
month. E.g., if YEAR_MONTH == 201301 then YEARMONTH_LAG1 = NA (as there is
no record for 201212, and there is none in my data as all starts from
201201). Similarly if YEAR_MONTH == 201302 then YEARMONTH_LAG1 = 201301.

2. ATT1_CHNG is the number of times the level has changed (i.e., from Y to
N and vice-verse) for 'ATT_1' in the previous month (i.e., in
YEARMONTH_LAG1)

3. ATT2_CHNG is the number of times the level has changed (i.e., from 0 to
1 and vice-verse) for ATT_2 in the previous month

How can this be done in R?
-- 
Regards
Abhinaba Roy

	[[alternative HTML version deleted]]

