SAS has also FINANCIAL FUNCTIONS for this type of calculations. Use for example the FINANCE ACCRINT Function: Computes the accrued interest for a security that pays periodic interest.   data _null_; issue =mdy(8, 28, 2021); firstinterest=mdy(8, 28, 2022); settlement =mdy(8, 28, 2022); rate =0.0575; par =5000; frequency =1; basis =1; r=finance('accrint', issue, firstinterest, settlement, rate, par, frequency, basis); put r=; my_r = 5000 * 1.0575; put my_r=; run; /* end of program */ Cheers, Koen   ... View more

Results2 is a library which you create with a libname statement. OUTPUT2 is the name of the data set created. ... View more

In challenge part i have to use macro variables to change values from mammals to birds using macro variables and have to generate freq report.   I think you're thinking about this too much in absolutes. Remember these are all examples, at a basic level and are not absolute you must do it this way examples. This is designed to illustrate how you can dynamically change the code in multiple places without changing things manually. Rather than "I have to use macro variables" it should be thought of as "The question asks me to use macro variables to change my proc freq report automatically". This is one way to accomplish this, there are others.    If you want to know why something is the way it is, try doing it without it and see what happens and compare them.  If you had used "data bird" in your code instead of data &category, each time you run it what will happen? Try doing it for Mammals now? And then Reptiles (or whatever category you have)? It will always write to a data set called Bird which will overwrite your old information. This type of approach allows you to modify your code in one place, rather than multiple places and tends to be less error prone as there's less room for someone to forget to change it in N locations. Your example likely only has one or two references, but what happens if you were using that variable in 50 different places in your code? Would you want to manually change that in each place or just once at the top of your code?   @AnuragRankja wrote: data step simply create output tables That's also a vast simplification of what a data step does. It does merges, can generate text files and can also not generate any output. It's used for a lot of wrangling in general.   @AnuragRankja wrote: I am new user of SAS, i have completed my pg1 base SAS course few days ago, Recently i am practicing my course notes where i am facing difficulty in lesson 4, page 167 in English pg1 pdf. In challenge part i have to use macro variables to change values from mammals to birds using macro variables and have to generate freq report. %let Category=Bird data &Category; set pg1.np_species; now i want to know that why we use "&Category " in data step? data step simply create output tables, so in general whatever name we want to give to the table we write it in data step but here we are using different technique can't we use "data bird;" in data step to create table named bird it self instead of this macro variables in data step? If we can't use "data bird;" so what is the reason? ... View more