Overview of Reading Variable-Length Records

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Reading Variable-Length Records

Lesson Overview

Introduction

Some operating systems have different types of record formats for external files. An external file that has a fixed-length record format has an end-of-record marker after a predetermined number of columns. A typical record length is 80 columns.

fixed-length record format

Or, external files can have a variable-length record format where an end-of-record marker is placed after the last field.

variable-length record format

When records contain fields of varying widths or a varying number of fields, then variable-length records can use space more efficiently. This lesson shows you how to determine the length of each record and read variable-length records.

This lesson contains 21 pages and takes approximately 30-45 minutes to complete.

Objectives

In this lesson, you learn how to

determine the length of each record
read character variables that have varying lengths.

You can also review how to

use a line-hold specifier to hold the current record
execute SAS statements based on a variable value
explicitly write an observation to a data set.

Prerequisites

Before taking this lesson, you should have completed the following lessons:

Getting Started with SAS Programming

Working in the SAS Environment
Basic Concepts
Editing and Debugging SAS Programs
Setting Up Your SAS Session

Creating SAS Data Sets

Reading Raw Data

Reading Various Types of Raw Data

Understanding DATA Step Processing
Reading Raw Data in Fixed Fields
Reading Free-Format Data
Creating Multiple Observations from a Single Record