SAS Data Set and Programming Basics

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SAS Data Set and Programming Basics

• STT 305

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SAS Programs

• SAS Programs consist of three major components
• Global statements
• Procedures
• Data steps

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SAS Programs
Global Statements
Procedures
Data Step
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Notes

• Data steps and procedures are made up of one or
  more statements.
• All statements end with a semicolon.
• This is the only restriction, SAS programs are
  otherwise free-forme.g. the following are
  equivalent
• proc sort datatotalrev
• by origin destination
• run
• proc sort datatotalrevby origin
  destinationrun

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Notes

• The run statement is optional (only the final one
  is required).
• The run statement indicates to SAS that the
  procedure or data step is complete.
• Starting a new data step or procedure is also
  taken by SAS as an indication that the previous
  one is complete (nesting of data steps and/or
  procedures is not allowed).
• Using the run statement is generally good
  practice

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SAS Data Set Basics

• SAS data set reference
• Two levels libref.data-set
• libref is the SAS library (work library is
  default if libref is omitted)
• data-set is the name of the SAS data set
• SAS naming conventions
• Names can be up to 32 characters in length
• Not case sensitive
• Must begin with a letter or underscore
• Contain only letters, numbers or underscores
• Applies to data sets, variables and libraries,
  but libraries are limited to 8 characters.

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SAS Data Libraries

• A SAS data library is a directory on your
  computer where SAS data sets are stored or will
  be stored.
• A library reference name (libref) can be assigned
  using the libname statement
• libname libref path-specification
• The libref must follow naming conventions and the
  path specified must exist.

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SAS Data Set Basics

• SAS data sets consist of two portions
• Descriptor portion
• Data portion
• Descriptor portion
• Contains various status information
• Can be viewed with PROC CONTENTS

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The Contents Procedure

• To view the descriptor portion of a data set
• proc contents datalibref.filename
• run
• To view data set listing for a particular
  library
• proc contents datalibref._all_ nods
• run

Keyword to display all data sets in library
Suppress descriptor portion
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SAS Data Set Basics

• Data portion
• Contains variable names and values
• Can be viewed with PROC PRINT or via the
  explorer.
• SAS variables and values are of two types
• Numeric
• Character

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Creating/Modifying SAS Data Sets

• The data step can be used to create a SAS data
  set using an existing SAS data set
• data output-data-set
• set input-data-set
• SAS statements
• run