SAS The language of Analytics Blog 1: Working with simple data sets

Welcome back to the world of analytics. Today's scope of coverage is how to write a simple SAS Programme.

 

About SAS:

 This is a very powerful tool that has been used across companies to take advantage of its statistical   capability.  The methodology adopted in this blog is through questions and understanding the output and code lines:

You have a text file called scores.txt containing information on gender (M or F) and four test scores (English, history, math, and science). Each data value is separated from the others by one or more blanks.

 a.    Write a DATA step to read in these values. Choose your own variable names. Be sure that the value for Gender is stored in 1 byte and that the four test scores are numeric.

b.    Include an assignment statement computing the average of the four test scores.

c.    Write the appropriate PROC PRINT statements to list the contents of this data set.

Code

1./*To calculate the average of the scores*/
2.title " Result of question1"
3.data scores;
4.infile "C:\Users\Elcot\Desktop\Term1\SAS Folders\Day 2\Set_1\scores.txt";
5.input gender $1 score1 score2 score3 score4 ;
6.avescore = mean(of score1-score4);
7.run;
8.proc print data = scores;
9.run;
10.proc contents data = scores;
11.run;

There are broadly two statements data and proc steps. Data statements are used to manipulate data, input data etc whereas proc which corresponds to procedure which  is used to summarizing reports and displaying output.

Lets drill down each line
1)    /* ….. */: It is the method to write the comments in the SAS
2)   Title is used to give the heading and it is one of the global statements which are valid for each sas  session
3)  This is using the data statement to create a file scores in the temporary folder work.
4)  Infile statement is used to import the file here we are importing the notepad file
5)  Input is used to declare the variables here gender is character variable other score 1 to score 4 are numeric . By default the size is 8 bytes but here we are declaring the size of gender as 1 byte
6) In this statement we are declaring a new variable avescore and = is used for assignment and mean function to calculate the mean
7) Run is important to end the data or proc statement
8) Proc print is the procedure to display the output of output in scores file.
9) Run is important to end the data or proc statement
10)   Proc contents to display the contents of the text file scores

  

   You want to create a test data set that uses a DATALINES statement to read in values for X and Y.  In the DATA step, you want to create a new variable, Z, equal to 100 + 50X + 2X² – 25Y + Y².   Use the following (X,Y) data pairs: (1,2), (3,6), (5,9), and (9,11).   


Code:
data  random;
input  X Y;
z = (100 + 50*X + (2*X)**2 - 25*Y + Y**2);
datalines;
1 2
3 6
5 9
9 11
;
run;
proc print data=random;
run;
Explanation: Datalines are used to input the data and the most important part here is the z variable the calculation basically follows the below mentioned route:  Paranthesis are also given preferences among any other operation

Output:

a) Never forget to end a statement with run ; otherwise the programme would not be executed

Reference:  Leaning SAS by example

Follow next blog for coverage of other topics