1. SAS Programming I Matthew A. Lanham Doctoral Student
September 20, 2018
SAS Programming I
Matthew A. Lanham
Doctoral Student
Virginia Polytechnic Institute and State University
Pamplin College of Business
Department of Business Information Technology

2. September 20, 2018

3. Short Course Outline A brief history of SAS
SAS Programming I
September 20, 2018
Short Course Outline
A brief history of SAS
How is SAS different from other software packages?
SAS Environment
SAS Data Libraries
Getting data into SAS using the IMPORT Wizard
Data Example: National Longitudinal Mortality Survey
SAS Programs – DATA and PROC Examples
Creating data from scratch
Merging data sets
Saving data sets
Basic Data Analysis PROCs
References
September 20, 2018
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4. History of SAS SAS Institute, Cary, NC
About SAS
SAS Programming I
September 20, 2018
History of SAS
SAS Institute, Cary, NC
Jim Goodnight and Anthony Barr co-founders
Began as a research project at NC State in 1966
Funding from NIH from
1976, 100+ customers, left NC State to form the SAS Institute, Inc.
1980s, one of Inc. Magazine’s fast growing companies, 1500 employees
1990s, 7000 employees
#1 on Fortune’s best places to work
2011, 11,000 employees, more than 50,000 customer sites and 200 products
Today
Holds largest market share for advanced analytics
Used by 79% of Fortune 500 companies
September 20, 2018
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5. How is SAS different from other software packages like R?
Similarities and Differences
SAS Programming I
September 20, 2018
How is SAS different from other software packages like R?
SAS versus R
SAS will require a license ($), R is open-source
Any statistical analysis you can do in SAS, you could probably do in R
SAS is commercial software so additions take longer. R has new libraries being added frequently.
SAS help and documentation is nice (like MATLAB). R documentation is lean.
SAS handles large data sets with ease. R stores everything in RAM making it vulnerable.
SAS and R are fairly easy to learn, but R feels more like typical programming.
SAS can be used like a database (PROC SQL) because of its design.
Popularity
Tiobe Sofware which ranks software popularity currently has SAS ranked #22 and R #24.
KDNuggets 2013 software poll for data science or big data: R (37%), SAS (11%), MATLAB (10%)
Rblogger.com - Number of Jobs on Indeed.com requesting skills in analytics: #1 SAS (12,272), #2 SPSS (3,289), #3 R (1,693)
SAS and R comparison code
Suggestions: Learn the basics of both and use as needed. You can work with both together.
I’ll use R packages if I don’t want to write methods myself and SAS doesn’t have a PROC for me to use.
September 20, 2018
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6. SAS Environment
SAS Programming I
September 20, 2018
SAS Environment
When you begin SAS, you should see 3 windows by default:
Log window – displays messages about your SAS session and submitted programs
Output window – “LISTING” output from programs submitted. Most results will show up in the “Results Viewer”
Enhanced Editor window – used to write and edit your programs
Log window
Output Window
Editor Window
September 20, 2018
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7. SAS Environment One the left hand side is where you will find:
SAS Programming I
September 20, 2018
SAS Environment
One the left hand side is where you will find:
Explorer window – allows you to view and manage your SAS files
Results window – helps you navigate and manage output from programs submitted. Uses a tree structure to list various types of output.
September 20, 2018
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8. SAS Statements
SAS Programming I
September 20, 2018
SAS Statements
Just like other languages you need to write code to get your program to do what you want it do to.
In SAS, we write SAS Statements which
Usually begin with a SAS keyword (DATA or PROC)
Always end with a semicolon (;)
SAS Statements
are free-format (can begin/end anywhere on a line, a statement can continue to multiple lines, or can have several statements on one line)
Blanks or special characters separate words
Usually end with a run; or quit;
September 20, 2018
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9. Temporary vs. Permanent SAS data libraries
SAS Programming I
September 20, 2018
SAS Data Libraries
SAS Data Library – a group of SAS files that are stored in the same directory.
Note: Only files with a SAS file extension (.sas7bat) are recognized, but you can store other files here.
Temporary vs. Permanent SAS data libraries
Temporary
Permanent
Data files only last for the current SAS session
Files remain there even after SAS closes until you delete them in the future
If you don’t specify a library name your file is stored in the “work” data library
If you specify a library, other than work, you are creating a permanent data set
September 20, 2018
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10. SAS Data Libraries - Examples
SAS Programming I
September 20, 2018
SAS Data Libraries - Examples
General Form: Temporary
You can qualify the filename
with work, but its not necessary
General Form: Permanent
We defined a library
called “thesis”
If we closed our SAS session now what do you think would happen?
DATA filename_new;
SET libref.filename_current;
RUN;
LIBNAME libref ‘SAS-data-library-location’;
DATA libref.filename_new;
SET libref.filename_current;
RUN;
September 20, 2018
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11. National Longitudinal Mortality Survey
NLMS Data
SAS Programming I
September 20, 2018
National Longitudinal Mortality Survey
Survey given by the Census Bureau.
Public access data -
This is the 3rd release (June 1, 2008)
38 variables; 988,346 observations
September 20, 2018
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12. Creating a SAS Data Set Using the Import Wizard
SAS Programming I
September 20, 2018
Creating a SAS Data Set Using the Import Wizard
File Import Data… Click Finish
Analysts’ Steps
Review the log for errors
Review data 1 5 2 6 7 3 4
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13. Typical formats for Import Wizard
Import Wizard Formats
SAS Programming I
September 20, 2018
Typical formats for Import Wizard
Microsoft Excel Workbook(*.xls *.xlsb *.xlsm *.xlsx)
Microsoft Access Database (*.mdb *.accdb)
Comma Separated File (*.csv)
Tab Delimited Files (*.txt)
JMP File (*.jmp)
SPSS File (*.spss)
Stata File (*.dta)
Others..
September 20, 2018

14. Creating a SAS Data Set Using the DATA step
Import Data Using DATA step
SAS Programming I
September 20, 2018
Creating a SAS Data Set Using the DATA step
In the Enhanced Editor:
Your SAS Log Window should look something like this:
Review the data set using the contents procedure (PROC CONTENTS): 1 2 3
September 20, 2018
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15. What was different among the Import Wizard and DATA step?
Outline
SAS Programming I
September 20, 2018
What was different among the Import Wizard and DATA step?
September 20, 2018
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16. What was different among the Import Wizard and DATA step?
Outline
SAS Programming I
September 20, 2018
What was different among the Import Wizard and DATA step?
September 20, 2018
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17. DATA steps versus PROC steps
SAS Programming I
September 20, 2018
DATA steps versus PROC steps
DATA steps – typically create or modify data sets, also used for custom reports.
PROC (procedure) steps – invoke or call pre-written routines and typically present the data in the form of a report
Examples
OPTIONS
PROC SORT
PROC PRINT
PROC CONTENTS
PROC COPY
PROC UNIVARIATE
PROC MEANS
PROC FREQ
PROC SUMMARY
PROC CORR
PROC REPORT
Number/nonumber
Date/nodate
pageno = 1
pagesize = 60
Yearcutoff = 1920
firstobs = 2
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18. Creating a new data set with assignment statements
DATA set manipulation
SAS Programming I
September 20, 2018
Creating a new data set with assignment statements
Use the DATA step with a SET statement
Specify new data set (libref.filename) You can use the “keep” option if you want certain variables
After SET specify SAS dataset to use
Everything else is optional. Here we stated that we only want data where martial status, death, and age is known. We then created two dummy variables. One for married male “mar_male” and unmarried male “unmar_male”
DATA libref.filename_new;
SET libref.filename_old;
<optional SAS statements>;
RUN; 1 2 3
September 20, 2018
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19. DROP and KEEP statements
DATA set manipulation
SAS Programming I
September 20, 2018
DROP and KEEP statements
You may use DROP or KEEP statements in either:
DATA statement, or
SET statement
We could use keep after SET and it tells SAS to look at these variables only.
Previous code: We had to “keep” all 3 newly created variables here
Alternative code: We don’t need too here, but must include indea b/c used in where
DATA libref.filename_new;
SET libref.filename_old;
<optional SAS statements>;
RUN;
September 20, 2018
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20. IF-THEN-ELSE Conditioning
DATA set manipulation
SAS Programming I
September 20, 2018
IF-THEN-ELSE Conditioning
SAS IF statements are similar to other languages
General Form:
Alternative code: Previously we created two new variables, but we could have created one
Alternative code 3: Here we used “mar_male” as our lone dummy variable
IF <expression 1> THEN <statement>;
ELSE IF <expression2> THEN <statement2>;
ELSE <statement3>;
September 20, 2018
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21. Conditional syntax Examples of conditional SAS syntax:
DATA set manipulation
SAS Programming I
September 20, 2018
Conditional syntax
Examples of conditional SAS syntax:
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22. PROCT SORT PROC SORT – sorts data according to specified variables
SAS Programming I
September 20, 2018
PROCT SORT
PROC SORT – sorts data according to specified variables
– must be used before a PROC PRINT statement
General Form:
By default, data is sorted in ascending order, but you may specify descending.
<options>
OUT= creates a data set of the sorted data. If not used, SORT overwrites the data set.
NODUPKEY removes duplicate observations that have the same values for the BY variables.
Example code: We sorted the data set by mar_male first, age second, etc.
Is our sorted data a temporary or permanent data set?
What would have happened if we didn’t use the out=nlms_ex4 statement?
PROC SORT data=libref.filename <options>;
BY <descending> variables;
RUN;
September 20, 2018
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23. PROC CONTENTS
SAS Programming I
September 20, 2018
PROC CONTENTS
PROC CONTENTS – use to create SAS output that describes either
The contents of a library
The descriptor portion of an individual data set
General Form:
Examples:
What do you think happens when
the nods option is removed?
PROC CONTENTS data=libref.filename <options>;
RUN;
September 20, 2018
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24. Creating Data Sets From Scratch
DATALINES, LINES, CARDS
SAS Programming I
September 20, 2018
Creating Data Sets From Scratch
You can create your own data set from scratch using a DATA step by using the DATALINES statement.
General Form:
In this case, a RUN; is not needed.
Examples:
DATA data=libref.filename;
INPUT <variables>;
DATALINES;
<data goes here> ;
September 20, 2018
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25. Creating Data Sets From Scratch
DATALINES, LINES, CARDS
SAS Programming I
September 20, 2018
Creating Data Sets From Scratch
More Examples:
September 20, 2018
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26. Combining data sets
SAS Programming I
September 20, 2018
Combining Data Sets
Concatenating/Appending – stacks each data set on the other
variables that are not in both data sets will have missing values for those variables not found in both
General Form:
Example:
Note: If you prefer you can use PROC APPEND instead of using the DATA step
DATA libref.filename;
SET filename1 filename2;
RUN;
September 20, 2018
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27. Combining data sets
SAS Programming I
September 20, 2018
Combining data sets
Merging – allows you to match observations from one data set to another.
Data must be sorted first to work (PROC SORT)
Two types of Merges:
One-to-One Match Merge – A single observation in one data set corresponds to a single record in other data sets.
One-to-Many Match Merge – A single observation in one data set corresponds to multiple observations in other data sets
General Form: Example:
DATA libref.filename;
MERGE filename1 filename2;
BY variable1 variable2;
RUN;
September 20, 2018
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28. One-to-many Match Merge
Combining data sets
SAS Programming I
September 20, 2018
One-to-many Match Merge
One-to-Many Match Merge – A single observation in one data set corresponds to multiple observations in other data sets
Example:
September 20, 2018
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29. Saving data sets
SAS Programming I
September 20, 2018
Saving Data Sets
You can use:(1) DATA statement, (2) PROC EXPORT, or (3) drop-down menu
General Form:
PROC EXPORT:
Using drop-down:
LIBNAME libref ‘SAS-data-library-location’;
DATA libref.filename_new;
SET libref.filename_current;
RUN; 2 3 1 4
September 20, 2018
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30. Data Analysis
SAS Programming I
September 20, 2018
Data Analysis
PROC UNIVARIATE and PROC MEANS are two procedures you might use to get an idea of the distribution of your attributes.
General Forms:
PROC UNIVARIATE libref.filename <options>;
VAR <variable list>;
RUN;
PROC MEANS libref.filename <options>;
VAR <variable list>;
RUN;
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31. Data Analysis
SAS Programming I
September 20, 2018
Data Analysis
PROC CORR will also provide some simple statistics like mean, standard deviation, etc.
General Forms:
PROC CORR libref.filename <options>;
VAR <variable list>;
WITH <variable list>;
RUN;
September 20, 2018
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32. References September 20, 2018 References SAS Programming I