Practical Data Management and Statistical Computing (BioEp691F)

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Outline: Lec1 Lec2 Lec3 Lec4 Lec5 Lec6 Lec7 Lec8 Lec9 Lec10
Lectures: Lec1 Lec2 Lec3 Lec4 Lec5 Lec6 Lec7 Lec8 Lec9 Lec10

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Lecture 9

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1. Reading ASCII data with more than one line per record.

Data may be entered with more than one line per record. A brief description of such data comes from the Shock Research Unit at the University of Southern California, Los Angeles, California. Data on many physiological variables were collected successively in time on each patient. These data represent a special subset of the data that was extracted for the purpose of exercise. Initial measurements (measurements upon admission) and final measurements on the same variables (measurements just before death or discharge) were collected on 113 critically ill patients. We first save these data in an ASCII file called shock.txt on the C:\DATA directory, and read the data with the program dmes99p10.sas. The program illustrates:

• use of / to move to a new line
• check for properly ordered lines of data
• check for matching values of a 'duplicate' variable
• subsetting variables with a KEEP option in a DATA statement

Formats for categorical variables can be saved in a permanent SAS data set. We illustrate this here for the SHOCK data. The program dmes99p11.sas illustrates:

• use of #1 to specify the line number of a record with multiple line data
• use of the CNTLOUT option in the PROC FORMAT statement.

The formats can be read in with a CNTLIN option in PROC FORMAT. For example, in another SAS session, prior to using the formats with a data set, include the format procedure:

PROC FORMAT CNTLIN=old.datf;

where old specifies the path to the SAS format data set named datf.sd2.

There are two differences for formats for character variables:

• the format name must begin with a $
• the character value must be enclosed in quotation marks

Example:

PROC FORMAT;

VALUE $sex

"F"="Female"

"M"=Male";