Christopher Toppe, Ph.D. Computer Sciences Corporation

Transcription

1 An Introduction to PROC TABULATE: A Hands-On Workshop Christopher Toppe, Ph.D. Computer Sciences Corporation Abstract The Tabulate procedure is, along with PROC REPORT, one of the most powerful and difficult report generation tools available to SAS programmers I analysts. Its power and its difficulty arise from the same fact: PROC TABULATE allows you to exercise nearly total control over both the contents and the appearance of its output. But the inherent complexity of this procedure should not stop you from becoming skilled at its use. As a matter of fact, an hour or two of structured ""1"'rience with PROC TABULA IE is enough to teach you how to control its major features and options, and to give you the tools you need to use this procedure with confidence in the future. 1ms workshop provides such an experience. It tackles PROC TABUlATE in a step-by-step fashion, building and enhancing a single table. 1ms paper is meant to accompany the workshop and presents the topics covered. However, only the final PROC TABULATE program, not each of the intermediate steps, has been included for reasons of space. 1ms workshop has been adapted from the esc course Getting Ihe Mosl OUI of PROC TABULATE, developed and taught by esc to its staff and clients. PROCTABULATE: Two Steps to Success I recommend that you envision the Tabulate Procedure as a two-step process, one to create the table and the other to enhance it. I further recommend that you approach PROC TABULATE as a series of minor steps that cascade into a fmal table. That is, build your table one step or enhancement at a time. Examine the impact of each change, making sure it did what you intended. Then move to the next enhancement. I recommend you follow this process because it is usually impossible to determine which part of a PROC TABULA IE is causing a problem when you are trying to build a finished table from scratch in one step. The Workshop Dataset The examples used in the workshop use a SAS dataset generated from the following code. The dataset contains 1,000 observations with four class variables, VARI - VAR4, and one analysis varoable, NUMVAR LIBNAME CSC "C:\CSC\TABULATE": OPTIONS PS=30 LS=70 NOCENTER: DATA CSC.TABDATA: RETAIN NUMVAR 0: DO H = 1 TO 125: DO I = 1 TO 2: DO J = 3 TO 4: DO K = 5 TO 6: DO L = 7 TO 8: VAR1=I: VAR2=J: VAR3=K: VAR4=L; NUMVAR+1: RANDOM=RANUNI(6): DROP I J K L; OUTPUT: END: END; END; END: END; PROC SORT; BY RANDOM: RUN: DATA FINAL: SET TEMP (OB5=1000) (DROP=RANDOM): RUN; Basic Syntax of PROC TABULATE PROC TABULATE DATA=SAS-data-set < options >: CLASS class-variables ; VAR analysis-variables ; TABLE table-specification < / 355

2 options> ; KEY LABEL keyword RUN;, label'... The TABLE statement must be present. By default, PROC TABULATE computes the frequency count (N) of class variables and the sum of analysis variables that are listed in the TABLE statement. If class variables are used in the TABLE statement, a CLASS statement is required. If analysis variables are used in the TABLE statement, a V AR statement is required. PROC TABULATE uses any variable labels that exist within the SAS data set. The CLASS Statement The CLASS statement identifies variables used to categorize, 0< classify, the data. Class variables are usually character variables or numeric variables with a small number of discrete values. The rows, columns, and pages of tables generated by PROC TABULATE are typically defined by class variables. In the workshop dataset, HOMETYPE and ST are class variables. The V AR statement TIle V AR statement identifies variables for which statistics are to be calculated and displayed in the PROC TABULATE output Analysis variables must be numeric variables. These variables are usually continuous; that is, they can possess many distinct values. In the workshop dataset, AMOUNT is the analysis variable. The TABLE statement TIle TABLE statement defines the table layout. Multiple TABLE statements can appear in a single PROC TABULATE step, each specifying a separate table. There are two key elements in formulating a table specification: Dimensions Variable combinations Table Dimensions Table dimensions are defmed by commas. Wherever you use a comma, you define another dimension of the table. If there are no conunas within the table specification, the output contains only columns -- no rows. If there is a single comma, then the table has two dimensions: rows and columns. Everything before the comma defines the rows, everything after the comma defines columns. A second comma defines the pages of the table. Everything before the first comma defines the pages, everything between the two commas defines the rows, everything after the second comma defines columns. Variable Combinations Variables in the table specification can be combined in two ways: Concatenation: variables separated by blanks Crossing: variables separated by asterisks In a concatenation, the variables appear independently within the same dimension. In a crossing, the variables appear ~ within the same dimension. Universal Class Variable ALL PROC TABULATE has a universal class variable called ALL. As you might e""peet, this variable provides an additional column or row to a table representing the total of the individual columns or rows. You add this special row/column to the table by including the keyword ALL in the TABLE statement. Be careful when adding ALL to tables with concatenation or crossing. You may have to add parentheses '0' to produce the desired results. Specifying Formals in PROC TABULATE Formatting Class Variables When displaying headings for values of class variables, PROC TABULATE uses any format assigued during creation of the input SAS data set If no format has 356

3 been assigned to a class variable or the format assigned must be overridden, a FORMAT statement can be used within the TABULATE procedure to assign a temporary fonnat for that step only. Formatting Cell Values By default, PROC TABULATE uses the BESTl2.2 format to display computed cell values. This results in a default cell width of 12 characters. To override the default format used for every table cell, add the FORMAT= option to the PROC TABULATE statement. The new default format also adjusts the cell widths in the table. Format Modifiers in the TABLE Statement Format modifiers can be used in the TABLE statement to alter the display format of a selected pages, rows or columns. To specify a format modifier, cross (*) the variable with F= followed by the desired fonnat name. Since the format modifier only modifies a single occurrence of a variable in a TABLE statement, it allows the use of different formats for a variable that appears multiple times in the TABULATE procedure output A format modifier may be applied to an analysis variable, a class variable, or the universal class variable ALL Specifying Labels in PROC TABUlATE Specifying Variable Labels When displaying headings for class and analysis variables, PROC TABULATE uses any label assigned during creation of the input SAS data set. If no label has been assigned to a variable or the label assigned must be overridden, a LABEL statement can be used within the TABULATE procedure to assign a temporary label for that step only. Using Label Modifiers in the TABLE Statement Label modifiers can be used in the TABLE statement to alter the label displayed for a given variable. To specii}' a label modifier, follow the variable name in the table specification with an equal sign (=) and a string enclosed in quotes. Since the label modifier only modifies a single occurrence of a variable in a TABLE statement, it allows the use of different labels for a variable that appears multiple times in the TABULATE procedure output, such as the universal class variable ALL A label modifier may be applied to an analysis variable, a class variable, or the universal class variable ALL. Labels for Key Words The KEYLABEL statement provides a way to override the default labels for key words such as ALL, N, and SUM. The label assigned with the KEYLABEL statement can be overridden by a label modifier in the TABLE statement. Suppressing Variable Labels Defining a blank label for a variable will suppress the printing of the corresponding table heading. Blank labels are most commonly used when a single statistic is generated for an analysis variable and the keyword heading is superfluous. PROC TABULATE Options Some of the other options which can specified on the PROC TABULATE statement include: FORMCHAR MISSING NOSEPS ORDER= The FORMCHAR Option defmes the characters used to construct the borders and separators of the table causes the display and inclusion of ntissing values for class variables generates output without separator lines between rows of the table specifies the ordering of class variable values FORMCHAR is used to define the II characters TABULATE uses to construct the outlines and dividers of the output table: the vertical and horizontal bar characters and the corner characters (upper left, upper ntiddle, upper right, middle left, ntiddle middle, middle right, lower left, lower ntiddle, lower right). The default value is ' '.!fthe string ' ab' were used to define the FORMCHAR, the resulting table boundaries would 357

4 look like: a222222b When specifying the FORMCHAR option, you must define all I I characters. The MISSING Option By default, missing values for class variables are suppressed by PROC TABULATE. By specifying the MISSING option in the PROC TABULATE statement, the procedure includes missing values (if any) in the output table. The NOSEPS Option When NOSEPS is specified in the PROC TABULATE statement, lines that are normally placed between rows of the output tables are eliminated. The separator lines are completely removed, not just replaced with blanks. The ORDER= Option When the TABULATE procedure generates the output table, the values of the class variables appear in sorted order according to the actual value stored in the input data set. By using the ORDER= option in the PROC TABULATE statement, the sequence in which values appear can be changed. There are four possible orders: ORDER=INTERNAL values are sequenced based on the actual stored value (the default) ORDER=FORMATIEDvalues are sequenced based on the fonnatted result ORDER=FREQ values are sequenced based on frequency in the input data set with the most common values appearing first ORDER=DATA OptWns on the TABLE Statement values are sequenced based on the order in which the values are encountered in the input data set Among the options which can be specified on the TABLE statement are: RTS= Row Title Spacing (also RTSPACE) defmes the number of spaces allotted to row titles CONDENSE MlSSTEXT= BOX= Requests that multiple logical pages be printed on a single physical page when possible Specifies up to 20 characters for PROC TABULATE to print in table cells that contain missing values Specifies the text to be placed in the empty area at the upper left corner above the row titles These options are specified after the table specification and are separated from the table specification by a single slash (I) character. Combinations of these options are allowed. The RTS= Option Specifying a value for RTS in the TABLE statement is the only way to control the width of the row titles. The default for RTS is one-fourth of the LINESIZE value. When specifying a value for RTS, that value must include space for the left and right vertical outline bars. The MISSTEXT= Option Specifying a text string (enclosed in quotes) with the MISSTEXToptioncausesPROC TABULATE to display the string within any cell that has a missing value The MISSTEXT string is limited to 20 characters. 358

5 The CONDENSE Option SpecifYing the CONDENSE option instructs PROC TABULATE to attempt to combine multiple logical pages into a single page whenever possible. The BOX= Option By default, the TABULATE procedure does not put any data in the upper left comer of the table. Using the BOX= option,proc TABUlATE can be instructed to place one of three items in the upper left comer of the table: BOX=]AGE_ Displays the pagedimension information in the box. If the page-dimension tex1 does not fit, it is placed in its normal position above the table and the box is left empty. BOX=variable Displays the name (or label) of a variable and its value in the box. BOX='string' Displays the quoted string in the box. Displaying Statistics and Percentages in PROC TABUlATE Specifying Statistics In addition to the default statistics (N for class variables and SUM for analysis variables), other statistics can be requested: MEAN STD MIN MAX NMISS The average value of the variable The standard deviation of the variable The minimum value of the variable The maximum value of the variable The number of missing values for the variable Statistics are calculated and displayed by following a class or analysis variable with an asterisk (*) and the statistic keyword in the TABLE statement. Class variables can only use the N and NMISS statistics. Analysis variables can use any of the available statistics. Multiple statistics can be generated for a variable by grouping the statistic keywords in parentheses. Displaying Percentages Two special statistics which can be displayed are PCTN (the percentage that one frequency represents of another frequency) and PCTSUM (the percentage that one sum represents of another sum). The most common use of this feature is to generate percentages that total to 100 either across a row or down a column. When using the default form of the percentage statistics, you may interpret the percentages in the following manner: Pretend that the corresponding N or SUM statistic is being generated. Accumulate the N or SUM values generated for.all values of the class variable(s) included in the dimension. Divide each N or SUM value by the accumulated total. SpecifYing Percentage Denominators When specifying PCTN or PCTSUM, PROC TABULATE can be instructed to use any class variable(s) as the denominator. This is accomplished by following the keyword PCTN or PCTSUM with the name(s) of the class variable(s) enclosed between the < and> symbols. To produce row-relative percentages, specify the column expression as the denominator. To produce column-relative percentages, specify the row expression as the denominator. Conclusion:!ftaken step by step, the TABULATE procedure can be a powerful new report writing tool. Attached are the workshop exercises. Notice we will be asking the class to build from simple to more complex. That is the way you should start to learn the TABULATE procedure. Please contact the author if you have any ftn1her questions, would like the finished code from the workshop or would like more information on CSC SAS programming or training services.. CSC Professional Services Group 130 I Piccard Drive, 2nd Floor Rockville, MD (301)

6 Workshop Exercises Build a table using PROC TABULA IE by following these instructions: I. Create a table with VAR3 as the colwnns and VARI as the rows. 2. Change that table to show V AR4 within V AR3 and V AR2 within V AR I. 3. Add the follo,",ing labels to the CLASS variables: VARI = 'OFFICE" V AR2 = "AGENT' V AR3 = "TYPE OF BUSINESS' V AR4 = "TYPE OF CUSTOMER'. NUMVAR = "ANNUAL PREMIUM" 4. Format each the the CLASS variables such that: V ARI, 1 ="Miami" and 2="Orlando' VAR2, 3="Jones" and 4="Johnson" V AR3, 5='Home Liability" and 6="Personal Auto" V AR4, 7="Repeat Client" and 8="New Client" 5. Add the universal variable ALL to each table dimension, making it the first variable listed. 6. Make the table show the total for the analysis variable NUMV AR in each cell. 7. Give the table the default format of DOLLAR1O. 8. Format the ALL variables into DOLLARI2. format. 9. Change the labels for ALL to 'TOTAL' for the rows and to "SUM" for the cohnns Remove the labels for the column variables. II. Make the table show two statistics, SUM and MEAN for the analysis variable. 12. Format SUM as DOLLAR I 2. and MEAN as DOLLAR Remove the separator lines. 14. Remove all separator characters. 15. Reduce the Row Title Space to Put the variable label for V ARI in the upper left box. 16. Make the table show the following percentages, one at a time: Percentage of each Office Percentage of each Type of Customer Percentage of Agent 360