Transcript The Infile Statement (covered in lecture)

The INFILE Statement
Reading files into SAS from an
outside source:
A Very Useful Tool!
Often the data you want to use are in
an outside source, such as an Excel
spreadsheet or text editor. You can
import these data into SAS with the
INFILE statement, rather than typing
in all of the data by hand.
In addition to coming from different
sources, the data may be delimited by
spaces, tabs, or commas. There are
codes to tell SAS what type of data it
will be reading into the Editor.
Basic SAS Code
The program you will use to read in a data
file will follow this basic format, with slight
variations:
DATA name of data set;
INFILE ‘C:\location and name of file’ ;
INPUT var1 var2 etc.;
RUN;
Let’s try a couple of examples.
Space delimited data with no
missing values and no labels
This will be the simplest type of data set you
could encounter. Download the file called
relief.txt, and save it to your hard drive
where you will be able to easily locate it.
Open SAS and type the following code into
your Editor window, keeping in mind that
the path to the file may be different on
your computer:
Sample Code
DATA relieftime;
INFILE ‘C:\Documents and Settings\My
Documents\relief.txt’ ;
INPUT group $ time;
TITLE ‘Reading in Data from an External
File’ ;
PROC PRINT DATA = relieftime;
RUN;
• The first line creates a data set called relieftime.
• The INFILE statement tells SAS where to find
the dataset.
• The third line labels the two variables in the data
set (just as you have seen before).
• The TITLE statement gives anything you print a
title.
• The PRINT statement prints your data in the
Output window, so that you can make sure you
did not lose any data.
• Try running the program in SAS. Were you
successful? Check your log for any ERROR
messages and try running the program again.
Check your log for valuable information. It tells
you how many observations were read into SAS,
and you can see if you are missing any data.
Output of PROC PRINT
Comma delimited data with missing
values and labels in the first row
You will also encounter comma-separated value (csv) files,
which are often created using Excel. To read in this type
of data, you will need to use the DSD option in your SAS
code.
Save the file about blood pressure (bp.csv) to your hard
drive, then type the following code into your Editor
window, keeping in mind the path to your file may be
different from the example.
Before you read the file into SAS, open it and look at the
format. Notice that first row contains variable names and
there are a few missing values. We will address that
using various SAS statements.
SAS Code
DATA bp;
INFILE 'C:\Documents and Settings\My Documents\bp.csv'
dlm = ',' dsd firstobs=2;
INPUT clinic $ dbp6 sbp6 dbpbl sbpbl;
TITLE 'Reading in .CSV Data from an External File';
PROC PRINT DATA = bp;
RUN;
• dlm [delimiter] = ‘,’ tells SAS that the data is delimited by
commas.
• dsd (delimiter-sensitive data) allows SAS to read in a
.csv file. This also allows SAS to recognize the missing
data.
• firstobs = 2 tells SAS to start reading the data from the
second row (because the first row contains variable
labels).
SAS Log
PROC PRINT Output
Tab delimited Data
Other types of data may be tab delimited,
and this is specified in the dlm option. We
use the statement dlm = ’09’x. (’09’x is the
hexadecimal representation of the tab
character, but you don’t need to know that;
it’s basically the technical way of
specifying TAB as the delimiter.)
Download the file aplastic.txt, open it to see
that the data begin on the first line, then
read the file into SAS.
SAS Code for Tab Delimited Data
DATA practice;
INFILE 'C:\Documents and Settings\My Documents\aplastic.txt'
dlm = '09'x firstobs=1;
INPUT ret lymph;
TITLE 'Reading in Tab-Delimited Data from an External File';
PROC PRINT DATA = practice;
RUN;
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After running this program, check your SAS log.
Are there any Errors or Warnings?
If not, look at your Output.
Is any data missing?
SAS Log
PROC PRINT Output
Conclusions
These are just a few examples of the most
common types of files you may encounter when
reading in an external data file into SAS using
the INFILE statement.
This skill will be valuable for future tutorials and
homework assignments.
Here are some helpful links for more info:
UCLA Academic Technology Services
University of Michigan Software Help
University at Albany CSDA