SAS is considered self-documenting because during the compilation time it creates and stores all the information about the data set like the time and date of the data set creation later No. of the variables later labels all that kind of info inside the dataset and you can look at that info using proc contents procedure. ... View more

% Local is a macro variable defined inside a macro. %Global is a macro variable defined in open code (outside the macro or can use anywhere). ... View more

Index function – Searches a character expression for a string of characters  SAS Statements Results a=’ABC.DEF (X=Y)’; b=’X=Y’; x=index(a,b); put x; 10 ... View more

Interleaving combines individual, sorted SAS data sets into one sorted SAS data set. For each observation, the following figure shows the value of the variable by which the data sets are sorted. You interleave data sets using a SET statement along with a BY statement. In the following example, the data sets are sorted by the variable Year. We can sort and then join the datasets on Year with the below code. Data combined; Set data1 data2 By Year; Run; ... View more

The main difference is that while reading an existing data set with the SET statement, SAS retains the values of the variables from one observation to the next. Whereas when reading the data from an external file, only the observations are read. The variables will have to re-declared if they need to be used. ... View more