The ELSE statement, if used, must immediately follow the IF-THEN statement. Using IF-THEN statements without the ELSE statement causes SAS to evaluate all IF-THEN statements. Using IF-THEN statements with the ELSE statement causes SAS to execute IF-THEN statements until it encounters the first true statement.
Do IF-THEN SAS?
An if-then statement can be used to create a new variable for a selected subset of the observations. For each observation in the data set, SAS evaluates the expression following the if. When the expression is true, the statement following then is executed.
How do you write an if statement in SAS?
IF (condition is true) => It means subsetting a dataset. The output is shown below : IF ID LE 100 => This would tell SAS to retain only those IDs whose values are less than or equal to 100.
Do you need an else statement in SAS?
The ELSE statement is optional. It can be used to execute a statement if the condition is not true.
What is the difference between IF and ELSE IF in SAS?
If the conditions that are specified in the IF clause are met, the IF-THEN statement executes a SAS statement for observations that are read from a SAS data set, for records in an external file, or for computed values. An optional ELSE statement gives an alternative action if the THEN clause is not executed.
Do loops in SAS?
Iterative DO loops are the simplest form of DO loops that can be executed within a SAS Data Step. The actions of an iterative DO loop are unconditional, meaning that if you define a loop to execute 50 times, it will execute 50 times without stopping (unless an error occurs during processing).
What is lag SAS?
In SAS, the LAG function is used to compare the current value to its predecessors. If you want to calculate lag of second order, use LAG2 function. Similarly, you can use LAG3 function for measuring lag of third order.
What is %let in SAS?
%let creates a macro variable. The value of the macro variable is stored in the macro table. Before the value of the macro variable goes into the symbol table, macro triggers ( & and % are resolved or executed).
What does a period mean in SAS?
In SAS Missing values for numeric variables (including date variables) appear as a period. SAS treats numeric nulls as equal to “the lowest possible number” (essentially negative infinity) when sorting a numeric field. SAS datasets will have a period as a value for missing data.
What does _N_ mean in SAS?
What is the automatic variable _n_? When you open a SAS data file in a data library, you will notice the observations are numbered at the first column. The automatic variable _n_ represents the observation numbers. This variable hidden in the DATA step is simple yet powerful in programming practice.
What is %do in SAS?
The iterative %DO is very similar to the DO statement used in the DATA step, but it is not confined to the DATA step. The iterative %DO defines and increments a macro variable. This paper presents a number of examples to demonstrate how to take advantage of the %DO loop to build SAS statements dynamically.
Do until in SAS?
DO UNTIL (expression); action statements; END; where expression is any valid SAS expression enclosed in parentheses. The key thing to remember is that the expression is not evaluated until the bottom of the loop. Therefore, a DO UNTIL loop always executes at least once.
Do loop in data step SAS?
Iterative DO loops are the simplest form of DO loops that can be executed within a SAS Data Step. The actions of an iterative DO loop are unconditional, meaning that if you define a loop to execute 50 times, it will execute 50 times without stopping (unless an error occurs during processing).
What is a SAS statement?
A SAS Program consists of a series of SAS statements which are used to define, read in, manipulate, and analyze data. Almost all SAS statements begin with a SAS keyword (except assignment statements), e.g. data, set, proc, infile, input, etc. All SAS statement has to end with a ; (semicolon).
What is the function of SAS?
SAS – Functions. SAS has a wide variety of in built functions which help in analysing and processing the data. These functions are used as part of the DATA statements. They take the data variables as arguments and return the result which is stored into another variable.
