sas fundamentals 1.1

8/2/2019 SAS Fundamentals 1.1

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SAS Fundamentals

Prepared By :G . NarasimhanTCS , Sholinganallur07/07/2003


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SAS Overview

SAS stands for Statistical Analysis System

Developed by SAS Institute

High Level Language

Fourth Generation Language


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SASSoftwares

BASE SAS

SAS / ACCESS

SAS / AF

SAS / CONNECT

SAS / FSP

SAS / GRAPH

SAS / NVISION

SAS / SHARE

There are a variety of SAS softwares. Few mostly used are ,


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SAS Softwares

SAS Software Applications

BASE SAS Report Generation , Mathematical and Data Analysis

SAS / ACCESS Interface to DB2

SAS / AF User friendly windowing applications

SAS / CONNECT Communication with remote SAS sessions

SAS / FSP Interactive data entry & retrieval facilities

SAS / GRAPH Visual representation of data analysis

SAS / NVISION Creation of 3D objects , animation & prototyping

SAS / SHARE Concurrent update access to SAS files


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Applications

Statistical & Mathematical analysis

Report Generation

Graphics

Business Forecasting

Animation

Modelling

Data Analysis

Operations Research


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Features of SAS

Portability

Free format language

Statements are not case sensitive

Enables Macro facility to simplify code development

Key words can be used as variable names

Declaration of variables not required

Statements can span more than one line

More than one statement can be placed on a single line


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Understanding SAS Dates

In SAS every date is an unique number

Dates before January 1 , 1960 are considered

as negative numbers

Dates after January 1 , 1960 are considered

as Positive numbers


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Understanding SAS Dates

Jan. 1, Jan. 1, Jan. 1,

1959 1960 1961

-365 0 366


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Every statement must end with a semicolon

Variable names must begin with an alphabet and should not

exceed eight characters

Variable names should not have embedded blanks

Variable names should not have SAS automatic variable names

Comments can be demarked by /* and */ symbols or by *

Rules of SAS Language


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SAS variables can be classified as follows:

Numeric Variables

Character Variables

Macro Variables

SAS Variables


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Numeric Variables

Stores a maximum of 8 bytes

Character Variables

Stores a maximum of 200 bytes

Macro Variables

Represented with a & prefix

SAS Variables


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Every SAS variable can have a maximum of six attributes assignedto it . They are ,

NAME - Variable Name TYPE - Variable Type LENGTH - Number of bytes variable can store FORMAT - Instructions that tell SAS system to write data

values

INFORMAT - Instructions that tell SAS system to read datavalues into variables

LABEL - Label assigned to a variable

Attributes of a SAS Variable


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Informats are special instructions used to read data values intoa variable.

Some of the Informats are :

$CHARw. Reads character data with blanks

COMMAw.d Removes embedded characters

DATEw. Reads Date in the form of ddmmyy

$W. Reads standard character data

Selected INFORMATS


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Formats are special instructions SAS System uses to write data valuesinto variables.

E.g :

$CHARW. Writes standard character data

BESTW. Default format for writing numericvalues

COMMAW.d Writes numeric values with commas

separating every three digits

Selected FORMATS


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DATEW. Writes data in the form of dates

( ddmmmyy )

DOLLARW.D Writes numeric values with dollar

signs,commas and decimal points

Selected FORMATS


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Two Automatic variables ( numeric ) are created for each DATA stepProcessing . They are ,

_N_

_ERROR_

_N_ : Initially set to 1 . Increments by 1 each time the DATAstep iterates.

_ERROR_ : Default value is 0 . Set to 1 whenever an error isencountered.

SAS Automatic Variables


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SAS Operators can be classified as :

Arithmetic Operators

Comparison Operators

Logical Operators

SAS Operators


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Operation Symbol E.g Meaning

Addition + X=Y+Z; Adds Y and Z

Subtraction - X=Y-Z; Subtracts Z

from Y

Multiplication * X=Y*Z; Multiplies Y

by Z

Division / X=Y/Z; Divides Y by Z

Exponentiation ** X=Y**Z; Raises Y to the Zpower

Arithmetic Operators


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Symbol MnemonicOperator

Meaning

= EQ Equal to

~= or ^= NE Not equal to

> GT Greater than

< LT Less than

>= GE Greater than or Equal to


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Symbol Mnemonic Operator

& AND

| OR

~ or ^ NOT

Logical Operators


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Symbol Mnemonic Operator

||

( Concatenation)

>< MIN( )

MAX( )

Other Operators


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SAS Program

A SAS Program is a collection of SAS steps. SAS steps can eitherbe

DATA step ( or )

PROC Step

DATA step starts with the key word DATA. It is used for creatingSAS

Data sets

PROC step is used for accessing the SAS Datasets


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SAS Step Boundaries

SAS Step boundary can be identified in two ways.

RUN statement

Beginning of next SAS step

A run statement marks the end of a SAS step. In case no runstatement is present , then the beginning of next SAS step marksthe

end of previous SAS step.


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SAS Step Boundaries

SAS step boundary terminated by RUN statement

E.g. : /* SAS step1 */

DATA sample ;

INFILE ext;

INPUT @001 name @030 age;

RUN;

/* SAS step2 */

PROC PRINT DATA = sample;

RUN;


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SAS Step Boundaries

SAS step boundary terminated with out a RUN statement

E.g. : /* SAS step1 */

DATA sample ;

INFILE ext;

INPUT @001 name @030 age;

;

/* SAS step2 */

PROC PRINT DATA = sample;

RUN;


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Batch Mode Interactive Mode

SAS Program

Running SAS Programs


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Batch ModeIn this mode , SAS Programs can be submitted through JCLs

Interactive ModeThis mode demands for a SAS session called Display ManagerSession ( DMS ). This is a user friendly environment .DMS screen is split into two halves namely SAS Log and ProgramEditor.

The upper half contains SAS Log and the lower half containsthe Program Editor. SAS Programs can be keyed in and executedfrom Program Editor.

Running SAS Programs


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SAS Output

When you execute a SAS program, the output generatedby SAS is divided into two major parts namely ,

( i ) SAS Log & ( ii ) Output

SAS Log

Contains information about the processing of the SAS program,including any warning and error messages

OutputContains reports generated by SAS Procedures and DATAsteps

In Batch SAS , Output is routed to SASLIST by default .The outputcan also be routed to an external file with the help of FILEstatement.


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SAS Output


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SAS Data Library General

Classification

SAS Data Library

SAS CatalogsOther FilesSAS Datasets

Membersof typeData

Membersof typeView

Membersof type

Catalog

Membersof typeAccess

Membersof type

Program


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SAS Data Libraries

SAS Data Libraries is a collection of SAS Files.

Each SAS Library can be Classified as

Work (or) Temporary Library

Permanent Library

A work Library is gets deleted after the end of a SAS session and is notavailable for further Sessions. It is referenced by a one level name orwith the first qualifier as WORK

A permanent library does not get deleted after a SAS session and isavailable all the time. It is referenced by a two level name . The firstlevel name should not be WORK


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Concept of Data sets

A SAS Dataset can be realised as a rectangular structurehaving a number of records in it with rows and columns.

Each row is referred to as an Observation ( Logically one record)

and the column names represent field names.

A SAS Dataset is different from a Mainframe Dataset

SAS Datasets are recognised only by the SAS System.

SAS Datasets can not be accessed by any other programminglanguages other than SAS.

SAS System can however fetch data from Mainframe Datasets.


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Descriptor

Information

Observation

Variable

SAS Data Set


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Descriptor Portion

The descriptor portionof a SAS data set contains :

General information about the SAS data set

( Data set name, number of observations, and so on)

Variable attributes

( Variable name, type, length, position, informat,

format, label )


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SAS Dataset Types

SAS Dataset

SAS Data File( Contains

Data Values )

SAS Data View( Does not contain

Data Values )


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Parts of a Dataset

Every SAS Data set has three elements namely

Libref Data set name Member TypeGeneral form of a SAS Data set is :

libref.data-set-name.member type

Where ,libref is the logical name of a SAS data library .data-setname is the dataset name member type is DATA for SAS data filesand VIEW for SAS data views.( This is assigned by the SAS system )


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Referencing a SAS Data set

A SAS Data set can be referenced by a Two - Level or One Levelname.

Two - Level NameSAS Data sets are stored permanently in a SAS library

General form : libref.data-set-name

One Level NameSAS Data sets gets deleted at the end of the current SASsession

General form : data-set-name

These Data sets are assigned to a a scratch library calledWORK library.

G tti I f ti f R


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DataDATAStep

SASDatasets

PROCSteps

Information

GettingInformation from RawData


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Where do the data come from ?

Input to a SAS Dataset can be any external file , TSO file , PS ,member of a PDS , a VSAM file, SAS Dataset or even an

Excel file.

Data retrieved from external sources SHOULD be converted toa SAS Dataset. This is because SAS system will recognise onlySAS Datasets.


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DATA Step

SAS sores information in the form of SAS Datasets.

A SAS Dataset is created by using DATA statement.

E.G : DATA details ;

The above SAS creates a SAS Dataset called details .

Data to a SAS Dataset can be supplied through INFILE or CARDSor

CARDS4 statement


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NULL DATA Step

_NULL_ This is a Dataset which will not have any observations in it . Used for printing purposes Used for writing data onto the external files

E.g. : The following file will write the contents of a SAS datasetcalledinto the details into an external file called outfile . Physical

nameof outfile will be mentioned on JCL.

DATA _NULL_ ;SET details;FILE outfile ;PUT @001 EMPNO

@005 NAME;RUN;


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DATAn Naming Convention

When no dataset name is specified on a DATA statement , SASAutomatically names the Dataset created as

DATA1,DATA2DATAn.

This is called as DATAn Naming convention.


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Referencing the external file

The INFILE statement is used to reference the external file

where the raw data is available. Using INPUT statement

the data can be retrieved from the external file.

E.g. : DATAdetail ;

INFILEuhgxn0.extrnl.file

INPUT

@001 Name@032 Age

;

RUN ;


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These statements will create a SAS Dataset called detailcontaining

two fields Name and Age. The values for Name will be taken

column 1 of external file ( uhgxn0.extrnl.file ) and values for Agewill

be taken from column 32 of external file.

Referencing the external file


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Reading a SAS Data Set

Model AircraftID InServiceMF4000 010012 10890

LF5200 030006 10300

LF5200 030008 11389

Model AircraftID InServiceMF4000 010012 10890

LF5200 030006 10300

LF5200 030008 11389

DATAia.aircraftcap;

SET ia.aircraftdata;

RUN;

DATA Step

IA.AIRCRAFTDATA

IA.AIRCRAFTCAP


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Combining Datasets

Various types of combining Datasets are :

Concatenation

Merging

Interleaving

Updating


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ConcatenationCombines two or more datasets one after the other into a singledataset . This is accomplished using SET statement

Interleaving

Combines individual sorted datasets into one sorted dataset.This is accomplished using SETBY statement

MergingCombines observation from two or more datasets into a singleobservation in a new dataset .This is accomplished by MERGE and

MERGEBY statements.

Combining Datasets


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Updating

Replaces the value of variables in one dataset ( Master Dataset)with non missing values from another dataset ( Transaction

Dataset ). This is accomplished using UPDATEBY statement.

Combining Datasets


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DATAlist3;

SET list1 list2;

RUN;

Concatenation

LIST2Name AgeArijit 20

Mohan 22

Kumar 54

LIST1

Name AgeArijit 20

Mohan 22Kumar 54Rohit 18Raj 33Sekar 17

Name AgeRohit 18

Raj 33

Sekar 17

LIST3


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Merging can be classified as ,

One- to-One Merging

Match Merging

Merging


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One- to-One Merging

In One -to-One merging , no BY statement is used. The SAS systemcombines the first observation in all datasets named in MERGEStatement into first observation in new dataset , the second

observation

in all datasets into second observation in new data set and so on.

Match Merging

In Match merging Datasets are merged according to the variables

mentioned in the BY statement

Merging


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DATAnewpay;MERGEpayroll increase;

RUN;

One-to-One Merging

Name Age Sex

Anil 22 M

Roopa 21 F

Name Salary

Anil 34500

Roopa 26000

Kiran 22000

INCREASEPAYROLL

NEWPAY

Name Age Sex Salary

Anil 22 M 34500

Roopa 21 F 26000

Kiran . 22000


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DATAwork.three;MERGEwork.one work.two;

BYX;

RUN;

Match Merging

WORK.TWOX Y

1 A

2 B

3 C

X Z

1 A1

1 A2

2 B1

3 C13 C2

WORK.ONE

X Y Z1 A A11 A A22 B B13 C C13 C C2

WORK.THREE


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DATAlist3;

SET list1 list2;

BY name; RUN;

Interleaving

Name Age

Anil 33

Sunil 12

Name Age

Karthik 17

Prakash 43

LIST2LIST1

LIST3

Name Age

Anil 33Karthik 17

Prakash 43

Sunil 12


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DATAnewpay;

UPDATEpayroll increase;

BYName;

RUN;

UPDATING

Name Salary

Anil 24500

Hari 32000

Kiran 16000

INCREASEPAYROLL

NEWPAY

Name Salary

Anil 34500

Hari

Kiran 26000

Name Salary

Anil 34500

Hari 32000

Kiran 26000


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PROCEDURES

Procedures are used to perform operations on SAS Data set

SAS has got a number of Procedures

Procedures are represented by the keyword PROC

Few commonly and most widely used PROCS such as

CONTENTS , SORT , PRINT are discussed below.


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CONTENTS Procedure

Used to browse the Descriptor portion

Gives information about Data set and the variables present inthe Data set

General form of the CONTENTS procedure:

PROC CONTENTS DATA=SAS-data-Set;RUN;


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PROC CONTENTS

E.g. :

DATA ONE;

INPUT @001 NAME $15. @020 AGE 2.;

CARDS;RAMESH 12

GOPAL 34

RAJU 07

;

RUN;

PROC CONTENTS DATA = ONE;

RUN;


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PROC CONTENTS


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PROC CONTENTS


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Rearranges the observations in a SAS data set

Creates a new SAS data set containing the

rearranged observations

Sort on multiple variables

Sort in ascending (default) or descending order

Do not generate printed output Treats missing values as the smallest possible

value

SORT Procedure


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Sorting a SAS Data Set

General form of the PROC SORT step:

PROC SORT DATA=input-SAS-data-setOUT=output-SAS-data-set;

BY by-variable(s);OPTIONS

RUN;


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PROC SORT

E.g. :

DATA ONE;

INPUT @001 NAME $15. @020 AGE 2.;

CARDS;

RAMESH 12GOPAL 34

RAJU 07

RAJU 07

;

RUN;

PROC SORT DATA = ONE NODUPLICATES;

BY NAME;

RUN;

PROC SORT


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PROC SORT

The Data set Work.one will containonly three records. Duplicate

record RAJU is deleted.

Name Age

GOPAL 34

RAJU 07

RAMESH 12

PRINT P d


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Used to display the contents of a SAS Data set

PRINT Procedure

PROC PRINT < option list >;VARvariable-list;ID Variable-list;BY Variable-list;PAGEBY BY-Variable;SUMBY BY-Variable;SUM variable-list;

RUN;

S l SAS P


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Sample SAS Program

S l SAS P


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Sample SAS Program

S l O t t


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Sample Output


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Thank You !

sas fundamentals 1.1

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