SAS INTNX function ( add days, months, years, etc )
The INTNX function increments dates, times, or datetimes by specific or custom intervals.
Here is the basic syntax for INTNX:
INTNX(interval[multiple.shift-index], start, increment[, alignment])
The interval can be a set value like - DAY, WEEK, DTWEEK, YEAR, etc. You can also specify a custom interval. We will post more on that later.
The multiple is optional and used as such. If you want the interval to be a 2 year period or biennial, you could use YEAR2. It is the same with weeks. If you were calculating 2 week pay periods and you wanted to increment by such, you would declare the interval to be WEEK2.
The shift-index lets you define a starting point within the interval. An example would be to start the week on Monday. The interval designation should be WEEK1.2 .
The start is your date, time, or datetime at which you want to begin the increment.
Increment is a positive or negative integer representing the number of interval shifts that should be made from the start.
Alignment is an excellent tool. It allows you to designate at which point SAS should return within an interval. You can specify:
B - beginning
M - middle
E - end
S - same
The default for alignment is beginning.
SAS DIM function – Counting the elements in an array
The DIM function returns the number of literal elements in an array. It functions against multi-dimensional arrays as well as one-dimensional arrays.
1-dimensional array example
DIM(array_name)
Multi-dimensional array examples
DIM(m_array) -> returns the number of elements in the first dimension of the array
DIM5(m_array) -> returns the number of elements in the 5th dimension of the array
DIM(m_array, 5) -> returns the number of elements in the 5th dimension of the array
The classic use case for the DIM function is to return the number of elements in an array for the upper bound of a do loop process. Example:
array array_name(5) var1 var2 var3 var4 var5;
do i=1 to dim(array_name);
some SAS statements here
end;
SAS DIF function – Comparing previous records
The SAS DIF function is another useful tool for operating on previous records.
Lets say you want to know the difference in the last year's revenue and this year's revenue. Here is the data:
Year Revenue
2001 10,000
2002 30,000
2003 60,000
2004 100,000
data revenue1;
set revenue;
Rev_increase=dif1(revenue);
run;
Year Revenue Rev_increase
2001 10,000 .
2002 30,000 20,000
2003 60,000 30,000
2004 100,000 40,000
The dif functions compares the current record to the nth previous record.