Accessing Data and Creating Data Structures. SAS Global Certification Webinar Series

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1 Accessing Data and Creating Data Structures SAS Global Certification Webinar Series

2 Accessing Data and Creating Data Structures Becky Gray Certification Exam Developer SAS Global Certification Michele Ensor Senior Manager SAS Education

3 SAS Global Certification Webinar Series February 8, 2017 September 14, 2017 Today: January 18, 2018 Upcoming SAS Global Certification Webinars February 15: Managing Data - 11:00 a.m. 12:00 p.m. ET March 13: Generating Reports and Test Taking Strategies 11:00 a.m. 12:00 p.m. ET 3

4 Base Programming Exam Content Areas The intended candidate for the SAS Base Programming exam is someone with current SAS programming experience in the following five content areas: 1. Accessing Data 2. Creating Data Structures 3. Managing Data 4. Generating Reports 5. Handling Errors In addition, candidates should be familiar with the enhancements and new functionality available in SAS

5 Base Programming Exam Specifics The following are specifics of the SAS Base Programming for SAS 9 exam: multiple-choice and short-answer questions 110 minutes to complete exam Closed book Exam taken on a computer Score received after completing the exam Must achieve a score of % 70 correct to pass 5

6 1. Accessing Data 2. Creating Data Structures

7 Accessing Data The content area of Accessing Data includes the following topics: Use FORMATTED and LIST input to read raw data files. Use INFILE statement options to control processing when reading raw data files. Use various components of an INPUT statement to process raw data files including column and line pointer controls, and controls. Combine SAS data sets. Access an Excel workbook. 7

8 Using Formatted and List Input Formatted input is used to read standard and nonstandard raw data in fixed columns. DATA output-sas-data-set; INFILE 'raw-data-file' <options>; INPUT pointer-control variable informat ; RUN; The following are some of the common SAS informats: $w. $CHARw. $UPCASEw. w.d COMMAw.d DOLLARw.d COMMAXw.d DOLLARXw.d EUROXw.d PERCENTw.d MMDDYYw. DDMMYYw. DATEw. YEARw. 8

9 Using Formatted and List Input List input is used to read standard and nonstandard raw data separated by a delimiter. DATA output-sas-data-set; LENGTH variable(s) $ length; INFILE 'raw-data-file' <options>; INPUT variable <$> variable <:informat> ; RUN; A space (blank) is the default delimiter. Variables must be specified in the order in which they appear in the raw data file. The default length for character and numeric variables is eight bytes unless using a LENGTH statement. 9

10 Question 1 Given the following fixed column raw data file: Sue F $26 Bobby M $35 Given the following DATA step: data people; infile 'people.dat'; Name Gender Amt dollar3.; run; Which SAS data set is created? a. b. 10

11 Question 1 Given the following fixed column raw data file: Sue F $26 Bobby M $35 Given the following DATA step: data people; infile 'people.dat'; Name Gender Amt dollar3.; run; Which SAS data set is created? a. b. 11

12 Question 2 Given the following delimited raw data file: 12MAR2013 Shirt 1 01APR13 Toy 2 Given the desired SAS data set: Which statement correctly reads the raw data file? a. input Date:date. Product Quantity; b. c. input Date date. Product $ Quantity; input Date:date. Product $ Quantity; 12

13 Question 2 Given the following delimited raw data file: 12MAR2013 Shirt 1 01APR13 Toy 2 Given the desired SAS data set: Which statement correctly reads the raw data file? a. input Date:date. Product Quantity; b. c. input Date date. Product $ Quantity; input Date:date. Product $ Quantity; 13

14 Using INFILE Statement Options Options can be specified in the INFILE statement: INFILE 'raw-data-file' <options>; The following are some of the common INFILE statement options: DLM= DSD MISSOVER FIRSTOBS= OBS= 14

15 Which statement is true? Question 3 a. The DSD option sets the default delimiter to a comma. b. The DLM= option is specified in the INPUT statement. c. The OBS= option specifies the record number of the first record to read in an input file. d. The MISSOVER option causes SAS to read a new input data record if it does not find values on the current data record. 15

16 Which statement is true? Question 3 a. The DSD option sets the default delimiter to a comma. b. The DLM= option is specified in the INPUT statement. c. The OBS= option specifies the record number of the first record to read in an input file. d. The MISSOVER option causes SAS to read a new input data record if it does not find values on the current data record. 16

17 Using INPUT Statement Components Column and line pointer controls can be specified in the INPUT +n / #n In addition, the and double can be specified in the 17

18 Which statement is false? Question 4 a. column pointer control moves the pointer to column n. b. The double is specified in the INPUT statement. c. The / line pointer control advances the pointer to column 1 of the next input record. d. The single holds the input record for the execution of the next INPUT statement across iterations of the DATA step. 18

19 Which statement is false? Question 4 a. column pointer control moves the pointer to column n. b. The double is specified in the INPUT statement. c. The / line pointer control advances the pointer to column 1 of the next input record. d. The single holds the input record for the execution of the next INPUT statement across iterations of the DATA step. 19

20 Accessing and Combining SAS Data Sets The SET statement is used to read a SAS data set in a DATA step. DATA output-sas-data-set; SET input-sas-data-set; RUN; Also, the SET statement is used to concatenate data sets. Concatenating copies all observations from the first data set and then copies all observations from one or more successive data sets. DATA output-sas-data-set; SET input-sas-data-set1 input-sas-data-set2 ; RUN; 20

21 Accessing and Combining SAS Data Sets The MERGE statement with a BY statement enables for match-merging. DATA output-sas-data-set; MERGE input-sas-data-set1 input-sas-data-set2 ; BY <DESCENDING> by-variable(s); RUN; Match-merging combines observations from two or more SAS data sets into a single observation by matching up values of one or more common variables. 21

22 Accessing and Combining SAS Data Sets The following are a few of the data set options that can be used with the input SAS data set when accessing and combining data sets: IN= RENAME= FIRSTOBS= KEEP= DROP= OBS= 22

23 Given the SAS data sets Nc and Sc: Question 5 Given the following SAS program: data both; set nc sc; run; How many variables are in the final data set Both? 23

24 Given the SAS data sets Nc and Sc: Question 5 Given the following SAS program: data both; set nc sc; run; How many variables are in the final data set Both? 3 24

25 Given the SAS data sets One and Two: Question 6 Given the following SAS program: data all; merge one(in=a) two(in=b); by ID; if a and not b; run; How many observations are in the final data set All? 25

26 Given the SAS data sets One and Two: Question 6 Given the following SAS program: data all; merge one(in=a) two(in=b); by ID; if a and not b; run; How many observations are in the final data set All? 1 26

27 Accessing an Excel Workbook The LIBNAME statement can be used to assign a library reference name to a Microsoft Excel workbook assuming SAS/ACCESS Interface to PC File Format is available. LIBNAME libref EXCEL 'Excel-workbook'; LIBNAME libref PCFILES PATH='Excel-workbook'; LIBNAME libref XLSX 'Excel-workbook';. PROC CONTENTS DATA=libref._ALL_; RUN; LIBNAME libref CLEAR; 27

28 Accessing an Excel Workbook If using the EXCEL or PSFILES engine, worksheet names appear with a dollar sign at the end of the name. A SAS name literal is used to reference the worksheet. libref.'excel-worksheet$'n If using the XLSX engine, worksheet names do not appear with a dollar sign at the end of the name. libref.excel-worksheet 28

29 Question 7 Which program reads a sheet named July from the Excel workbook YR2017.xlsx? a. libname myxls excel 'YR2017.xlsx'; data july; set myxls.'july$'n; run; b. c. libname excel pcfiles 'YR2017.xlsx'; data july; set excel.'july$'n; run; libname myexcel xlsx 'YR2017.xlsx'; data july; set xlsx.july; run; 29

30 Question 7 Which program reads a sheet named July from the Excel workbook YR2017.xlsx? a. libname myxls excel 'YR2017.xlsx'; data july; set myxls.'july$'n; run; b. c. libname excel pcfiles 'YR2017.xlsx'; data july; set excel.'july$'n; run; libname myexcel xlsx 'YR2017.xlsx'; data july; set xlsx.july; run; 30

31 1. Accessing Data 2. Creating Data Structures

32 Creating Data Structures The content area of Creating Data Structures includes the following topics: Create temporary and permanent SAS data sets. Create and manipulate SAS date values. Export data to create standard and comma-delimited raw data files. Control which observations and variables in a SAS data set are processed and output. 32

33 Creating SAS Data Sets The DATA step can be used to create temporary or permanent SAS data sets. DATA libref.sas-data-set; <additional SAS statements> RUN; The LIBNAME statement is used to assign a library reference name (libref) to a SAS library. LIBNAME libref 'SAS-data-library'; Note: Work is the default temporary library. 33

34 Creating SAS Data Sets Multiple SAS data sets can be created in a DATA step. DATA SAS-data-set-1 < SAS-data-set-n>; The OUTPUT statement is used to direct output to a specific SAS data set. OUTPUT <SAS-data-set-1 SAS-data-set-n>; Note: An OUTPUT statement without arguments writes to every SAS data set listed in the DATA statement. 34

35 Creating SAS Data Sets The DATA step is processed in two phases. Compile the step Compilation Phase Success? No Next step Yes Initialize PDV to missing Execution Phase Execute SET statement End of file? Yes Next step Execute other statements Output to SAS data set 35

36 Question 8 Given the following SAS data set and program: data both; set project.orders; Total=Quantity*Price; run; Which statement is true? a. A permanent data set is created. b. The final data set contains six observations. c. The final data set contains three variables. d. The DATA step stops execution during the sixth iteration. 36

37 Question 8 Given the following SAS data set and program: data both; set project.orders; Total=Quantity*Price; run; Which statement is true? a. A permanent data set is created. b. The final data set contains six observations. c. The final data set contains three variables. d. The DATA step stops execution during the sixth iteration. 37

38 Which statement is true? Question 9 a. During the compilation phase, variables are assigned missing values. b. During the compilation phase, the program data vector (PDV) is created. c. During the execution phase, the descriptor portion of the SAS data set is created. d. During the execution phase, an input buffer is created if reading data from a SAS data set. 38

39 Which statement is true? Question 9 a. During the compilation phase, variables are assigned missing values. b. During the compilation phase, the program data vector (PDV) is created. c. During the execution phase, the descriptor portion of the SAS data set is created. d. During the execution phase, an input buffer is created if reading data from a SAS data set. 39

40 Working with SAS Date Values A SAS date value is stored as the number of days between January 1, 1960 and a specific date. A SAS date constant is used to refer to a SAS date value in a program. ' ddmmmyyyy ' d 40

41 Working with SAS Date Values Functions are used to extract information from a SAS date value or create a SAS date value. YEAR QTR MONTH DAY WEEKDAY TODAY DATE MDY Formats are used to display SAS date values. MMDDYYw. DDMMYYw. DATEw. YEARw. WORDDATE. WEEKDATE. Informats are used to convert data to a SAS date value. MMDDYYw. DDMMYYw. DATEw. 41 MONYYw. YEARw.

42 Question 10 Given the following SAS program: Which report output is correct? data dates; Birth='15MAY1964'd; Dow=weekday(Birth); Age=(today()-Birth)/365.25; format Birth weekdate.; run; proc print data=dates noobs; run; a. b. c. d. 42

43 Question 10 Given the following SAS program: Which report output is correct? data dates; Birth='15MAY1964'd; Dow=weekday(Birth); Age=(today()-Birth)/365.25; format Birth weekdate.; run; proc print data=dates noobs; run; a. b. c. d. 43

44 Exporting to Raw Data Files ODS statements can be used to create a raw data file. ODS CSVALL FILE='raw-data-file'; SAS code to generate a report(s) ODS CSVALL CLOSE; The EXPORT procedure can be used to create a raw data file. PROC EXPORT DATA=SAS-data-set OUTFILE='raw-data-file' DBMS=CSV DLM TAB <REPLACE> <LABEL>; DELIMITER='char'; RUN; 44

45 Exporting to Raw Data Files The DATA step can also be used to create a raw data file. DATA _NULL_; SET input-sas-data-set; FILE 'raw-data-file' <DSD>; PUT variable variable-n <:format> ; RUN; 45

46 Which statement is true? a. ODS CSVALL is part of Base SAS. Question 11 b. A style template is used when specifying the STYLE= option in the ODS CSVALL statement. c. SAS/ACCESS Interface to PC Files is needed to use the EXPORT procedure to create a delimited file. d. The EXPORT procedure can reference a raw data file with the DATA= option and the OUTFILE= option. 46

47 Which statement is true? a. ODS CSVALL is part of Base SAS. Question 11 b. A style template is used when specifying the STYLE= option in the ODS CSVALL statement. c. SAS/ACCESS Interface to PC Files is needed to use the EXPORT procedure to create a delimited file. d. The EXPORT procedure can reference a raw data file with the DATA= option and the OUTFILE= option. 47

48 Controlling Observations and Variables The DROP and KEEP statements can be used to control the variables in the output SAS data set. DROP variable-list; KEEP variable-list; The DROP= and KEEP= data set options can also be used to determine the variables in the output data set. SAS-data-set(DROP=variable-1 < variable-n>) SAS-data-set(KEEP=variable-1 < variable-n>) 48

49 Controlling Observations and Variables The WHERE statement and IF statement can be used to control the observations in the output SAS data set. The WHERE statement selects observations before they are brought into the program data vector. WHERE expression; The IF statement selects observations that were read into the program data vector. IF expression; 49

50 Controlling Observations and Variables An expression is a sequence of operands and operators that form a set of instructions that define a condition. Operands Arithmetic Operators Comparison Operators Logical Operators Special WHERE Operators character constants, numeric constants, date constants, character variables, and numeric variables exponentiation (**), multiplication (*), division (/), addition (+), and subtraction (-) EQ (=), NE, GT (>), LT (<), GE (>=), LE (<=), and IN AND (&), OR ( ), and NOT CONTAINS (?), BETWEEN-AND, IS NULL, IS MISSING, LIKE, SAME AND, and ALSO 50

51 Given the following input SAS data set: Question 12 Given the following SAS program: data class; set sashelp.class(drop=sex); keep Name Height Weight; if Age >= 13 then Group='Teen'; run; How many variables are in the final SAS data set? 51

52 Given the following input SAS data set: Question 12 Given the following SAS program: data class; set sashelp.class(drop=sex); keep Name Height Weight; if Age >= 13 then Group='Teen'; run; How many variables are in the final SAS data set? 3 52

53 Given the following input SAS data set: Question 13 Which step produces an error? a. data subset; set employees; Month=month(birth); if state='ca' and Month=3; run; b. data subset; set employees; Month=month(birth); where state='nc' and Month=3; run; 53

54 Given the following input SAS data set: Question 13 Which step produces an error? a. data subset; set employees; Month=month(birth); if state='ca' and Month=3; run; b. data subset; set employees; Month=month(birth); where state='nc' and Month=3; run; 54

55 Base Programming Exam Preparation Multiple resources are available for your exam preparation. 55

56 Books SAS Product Documentation Free SAS Product Documentation is available. 56

57 Books Certification Prep Guide The official prep guide covers all of the objectives tested in the exam. 57

58 BASE Programmer Certification Review Series communities.sas.com Find a Community Learn SAS SAS Certification Preparing for the Base Programming Exam September 14, 2017 Accessing Data and Creating Data Structures January 18, 2018 Managing Data February 15, 2018 Generating Reports and Test-Taking Strategies March 13,

59 How to Reach Certification Web: sas.com/certify Exam Registration pearsonvue.com/sas 59

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