Lesson 2 Topic - Reading in data Programs 1 and 2 in course notes –Chapter 2 (Little SAS Book)

Raw Data Read in Data Process Data (Create new variables) Output Data (Create SAS Dataset) Analyze Data Using Statistical Procedures Data Step PROCs

Raw Data Sources You type it in the SAS program Text file Spreadsheet (Excel) Database (Access, Oracle) SAS dataset

Data in Text Files Delimited data – variables are separated by a special character (e.g. a comma) Fixed position – data is organized into columns Text files are simple character files that you can create or view in a text editor like Notepad. They may also be created as “dumps” from spreadsheet files like excel.

Data delimited with spaces: C D A A C Note: Missing data is identified with a period.

Data delimited with commas C,84,138,93,143 D,89,150,91,140 A,78,116,100,162 A,.,.,86,155 C,81,145,86,140 Note: Missing data is identified with a period.

Data delimited by commas (.csv file) C,84,138,93,143 D,89,150,91,140 A,78,116,100,162 A,,,86,155 C,81,145,86,140 Note: Missing data is identified by multiple commas.

Column Data C D A A C Note: Missing data values are blank.

INFILE and INPUT Statements When you write a SAS program to read in raw data, you’ll use two key statements: The INFILE statement tells SAS where to find the data and how it is organized. The INPUT statement tells SAS which variables to read-in

Program 1 * List Directed Input: Reading data values separated by spaces; DATA bp; INFILE DATALINES; INPUT clinic $ dbp6 sbp6 dbpbl sbpbl; DATALINES; C D A A C ; RUN ; TITLE 'Data Separated by Spaces'; PROC PRINT DATA=bp; RUN; Obs clinic dbp6 sbp6 dbpbl sbpbl 1 C D A A C

PARTIAL SASLOG 1 DATA bp; 2 INFILE DATALINES; 3 INPUT clinic $ dbp6 sbp6 dbpbl sbpbl; 4 DATALINES; NOTE: The data set WORK.BP has 5 observations and 5 variables. NOTE: DATA statement used: real time 0.39 seconds cpu time 0.03 seconds

* List Directed Input: Reading data values separated by commas; DATA bp; INFILE DATALINES DLM = ',' ; INPUT clinic $ dbp6 sbp6 dbpbl sbpbl; DATALINES; C,84,138,93,143 D,89,150,91,140 A,78,116,100,162 A,.,.,86,155 C,81,145,86,140 ; RUN ; TITLE 'Data separated by a comma'; PROC PRINT DATA=bp; RUN;

* List Directed Input: Reading.csv files DATA bp; INFILE DATALINES DLM = ',' DSD ; INPUT clinic $ dbp6 sbp6 dbpbl sbpbl; DATALINES; C,84,138,93,143 D,89,150,91,140 A,78,116,100,162 A,,,86,155 C,81,145,86,140 ; TITLE 'Reading in Data using the DSD Option'; PROC PRINT DATA=bp; RUN; Consecutive commas indicate missing data

* List Directed Input: Reading data values separated by tabs (.txt files); DATA bp; INFILE DATALINES DLM = '09'x DSD; INPUT clinic $ dbp6 sbp6 dbpbl sbpbl; DATALINES; C D A A86155 C ; TITLE 'Reading in Data separated by a tab'; PROC PRINT DATA=bp; RUN;

* Column Input: Data in fixed columns. DATA bp; INFILE DATALINES ; INPUT clinic $ 1-1 dbp6 2-4 sbp6 5-7 dbpbl 8-10 sbpbl ; DATALINES; C D A A C ; Title 'Reading in Data using Column Input'; PROC PRINT DATA=bp; Note: missing data is blank

* Reading data using Pointers and Informats DATA bp; INFILE DATALINES ; clinic dbp6 sbp6 dbpbl sbpbl 3. ; DATALINES; C D A A C ; Title 'Reading in Data using Point/Informats'; PROC PRINT DATA=bp; Informats must end with a period.

* Reading data using Informat Lists DATA quallife; INFILE DATALINES ; INPUT (QL1-QL35) (1.) ; DATALINES; ; Title 'Reading in Data using Informat Lists'; PROC PRINT DATA=quallife; VAR QL1-QL35; RUN; O Q Q Q Q Q Q Q Q Q L L L L L L L L L L L L L L L L L L L L L L L L L L b L L L L L L L L L s

Program 2 * Reading data from an external file DATA bp; INFILE ‘C:\SAS_Files\bp.csv' DSD FIRSTOBS = 2; INPUT clinic $ dbp6 sbp6 dbpbl sbpbl ; TITLE 'Reading in Data from an External File'; PROC PRINT DATA=bp; clinic,dbp6,sbp6,dbpbl,sbpbl C,84,138,93,143 D,89,150,91,140 A,78,116,100,162 A,,,86,155 C,81,145,86,140 Content of bp.csv

PARTIAL SAS LOG 7 DATA bp; 8 INFILE 'C:\SAS_Files\bp.csv' DSD FIRSTOBS=2 ; 9 INPUT clinic $ dbp6 sbp6 dbpbl sbpbl ; NOTE: The infile 'C:\SAS_Files\bp.csv' is: File Name=C:\SAS_Files\bp.csv, RECFM=V,LRECL=256 NOTE: 5 records were read from the infile 'C:\SAS_Files\bp.csv'. The minimum record length was 10. The maximum record length was 16. NOTE: The data set WORK.BP has 5 observations and 5 variables. NOTE: DATA statement used (Total process time): real time 0.10 seconds cpu time 0.01 seconds

*Reading data from an external file using a FILENAME statement; FILENAME bpdata ‘C:\SAS_Files\bp.csv'; DATA bp; INFILE bpdata DSD FIRSTOBS = 2; INPUT clinic $ dbp6 sbp6 dbpbl sbpbl ; TITLE 'Reading in Data Using FILENAME'; PROC PRINT DATA=bp;

* Using PROC IMPORT to read in data ; * Can skip data step; * Can also try IMPORT Wizard; PROC IMPORT DATAFILE=‘C:\SAS_Files\bp.csv' OUT = bp DBMS = csv REPLACE ; GETNAMES = yes; GUESSINGROWS=9999; TITLE 'Reading in Data Using PROC IMPORT'; PROC PRINT DATA=bp; PROC CONTENTS DATA=bp; Uses first row for variable names

* PC SAS can read excel files directly; PROC IMPORT DATAFILE=‘C:\SAS_Files\bp.xls' OUT = bp DBMS = xls REPLACE ; GETNAMES = yes; TITLE 'Reading in Data from excel'; PROC PRINT DATA=bp; PROC CONTENTS; Uses first row for variable names

The CONTENTS Procedure Data Set Name WORK.BP Observations 5 Member Type DATA Variables 5 Alphabetic List of Variables and Attributes # Variable Type Len Format Informat 1 Clinic Char 1 $1. $1. 2 DBP6 Num 8 BEST12. BEST32. 4 DBPBL Num 8 BEST12. BEST32. 3 SBP6 Num 8 BEST12. BEST32. 5 SBPBL Num 8 BEST12. BEST32.

SOME INFILE OPTIONS OBS - limits number of observations read FIRSTOBS - start reading from this obs. MISSOVER and TRUNCOVER - used to read in data with short records TERMSTR= used when reading PC files on a UNIX machine (or vice versa) LRECL= needed when you have data with long records (> 256 characters)

Problem when reading past default logical record length; DATA temp; INFILE ‘C:\SAS_Files\tomhs.data' OBS=6 ; jntpain 2. ; TITLE 'Data not read in correctly because variable is past default LRECL of 256'; PROC PRINT; Obs jntpain NOTE: Invalid data for jntpain in line 2 NOTE: SAS went to a new line when INPUT statement reached past the end of a line

*Add LRECL option to fix problem ; DATA temp; INFILE ‘C:\…\tomhs.data' OBS=6 LRECL=500; jntpain 2. ; TITLE 'Data read in correctly using LRECL option'; PROC PRINT; Obs jntpain

Reading Special Data 04/11/1982Date 59,365Comma in number Long (>8) characters Informat 04/11/1982mmddyy10. 59,365comma $11.

* Reading special data with fixed position data; DATA info; INFILE DATALINES; ssn taxdate income comma6. ; DATALINES; /12/ , /15/ , /15/ ,999 ; TITLE 'Variables with Special Formats'; PROC PRINT DATA=info; FORMAT taxdate mmddyy10.; Obs ssn taxdate income /12/ /15/ /15/

* Reading special data with list input using colon modifier; DATA info; INFILE DATALINES DLM=“;” DSD; INPUT ssn : $11. taxdate : mmddyy10. income : comma6. ; DATALINES; ;04/12/2001;59, ;03/15/2002;26, ;04/15/2003;44,999 ; TITLE 'Variables with Special Formats'; PROC PRINT DATA=info; FORMAT taxdate mmddyy10.; Obs ssn taxdate income /12/ /15/ /15/

* Using INFORMAT statement to supply input formats; DATA info; INFILE DATALINES DLM=“;” DSD; INFORMAT ssn $11. taxdate mmddyy10. income comma6.; INPUT ssn taxdate income ; DATALINES; ;04/12/2001;59, ;03/15/2002;26, ;04/15/2003;44,999 ; TITLE 'Variables with Special Formats'; PROC PRINT DATA=info; FORMAT taxdate mmddyy10.; Obs ssn taxdate income /12/ /15/ /15/

Summary of Ways of Reading in Data List input - data is separated by a delimiter; must read in all variables. Column input - data is in fixed columns;must know where each variable starts and ends; can read in selected variables Pointers and Informats - alternative to column input; most flexible; must be used for special data PROC IMPORT