Compute Blocks in Report

Transcription

1 Compute Blocks in Report

2 Compute Blocks Though it is always possible to compute new variables inside a data step, PROC REPORT allows for similar computations to be done internally as well. Computations are handled inside compute blocks syntax: compute attribute; SAS Statements The attribute may be a new variable, which will need to be defined in the column statement and likely given a define statement, but it may also be a different object. In either case, it is a block that opens with compute and is closed with endcomp.

3 Basic Example Given the report code below (and associated formats, not shown), suppose we want to change the birth weight summaries to pounds. proc report data=stt592.birthweight nowd; where race le 9 and smoke le 3; column smoke race gestation birth_wt=num birth_wt=avg; define smoke /format=smoking. group 'Smoking Status'; define gestation/format=term. group 'Gestation Period'; define race/format=race. group "Mother's Race"; define num/n 'Number of Cases'; define avg/mean 'Mean Birth Weight (oz.)' format=8.2; break after race/skip; break after smoke/summarize ol skip suppress; run;

4 Basic Example Instead of creating a new data set with that variable, we can complete this in report: proc report data=stt592.birthweight nowd; where race le 9 and smoke le 3; column smoke race gestation birth_wt=num birth_wt=avg wt_lb; define smoke /format=smoking. group 'Smoking Status'; define gestation/format=term. group 'Gestation Period'; define race/format=race. group "Mother's Race"; define num/n 'Number of Cases'; define avg/mean 'Mean Birth Weight (oz.)' format=8.2; break after race/skip; break after smoke/summarize ol skip suppress; compute wt_lb; run; wt_lb=avg/16;

5 Basic Example Instead of creating a new data set with that variable, we can complete this in report: proc report data=stt592.birthweight nowd; where race le 9 and smoke le 3; column smoke race gestation birth_wt=num birth_wt=avg wt_lb; define smoke /format=smoking. group 'Smoking Status'; define gestation/format=term. group 'Gestation Period'; define race/format=race. group "Mother's Race"; define num/n 'Number of Cases'; define avg/mean 'Mean Birth Weight (oz.)' format=8.2; break after race/skip; break after smoke/summarize ol skip suppress; compute wt_lb; run; wt_lb=avg/16; Define a compute block for that variable including its definition (based on the alias) Add a variable

6 Partial Result

7 Compute Blocks Rules: When computing a new variable, the compute block must reference that variable name in its opening line. Though the compute block may consist of several internal statements, one of these must assign a value to the variable. Any computations can only be based on variables/aliases that are in the column statement and also precede the computed variable. For summary statistics generated using an aliased column, refer to the alias for computations. If it is not aliased, the reference is variable.stat-keyword. Since no define statement is active, the column is established with the most basic options, but adding define options is possible:

8 Basic Example--Extended Instead of creating a new data set with that variable, we can complete this in report: proc report data=stt592.birthweight nowd; where race le 9 and smoke le 3; column smoke race gestation birth_wt=num birth_wt=avg wt_lb; define smoke /format=smoking. group 'Smoking Status'; define gestation/format=term. group 'Gestation Period'; define race/format=race. group "Mother's Race"; define num/n 'Number of Cases'; define avg/mean 'Mean Birth Weight (oz.)' format=8.2; define wt_lb/computed 'Mean Birth Weight (lb.)' format=8.2; break after race/skip; break after smoke/summarize ol skip suppress; compute wt_lb; run; wt_lb=avg/16;

9 Basic Example--Extended Instead of creating a new data set with that variable, we can complete this in report: proc report data=stt592.birthweight nowd; where race le 9 and smoke le 3; column smoke race gestation birth_wt=num birth_wt=avg wt_lb; define smoke /format=smoking. group 'Smoking Status'; define gestation/format=term. group 'Gestation Period'; define race/format=race. group "Mother's Race"; define num/n 'Number of Cases'; define avg/mean 'Mean Birth Weight (oz.)' format=8.2; define wt_lb/computed 'Mean Birth Weight (lb.)' format=8.2; break after race/skip; break after smoke/summarize ol skip suppress; compute wt_lb; run; wt_lb=avg/16; Note the computed attribute

10 Partial Result

11 Basic Example--Extended Of course, I may well not want to display both pounds and ounces, but I cannot simply remove the column for pounds--you can try it, but remember this rule: Any computations can only be based on variables/aliases that are in the column statement and also precede the computed variable. So it is sometimes necessary to include a variable (or aliased version of it) in the column statement, but not have it actually display in the report. This can be accomplished with the noprint option in the define statement

12 Basic Example--Extended Instead of creating a new data set with that variable, we can complete this in report: proc report data=stt592.birthweight nowd; where race le 9 and smoke le 3; column smoke race gestation birth_wt=num birth_wt=avg wt_lb; define smoke /format=smoking. group 'Smoking Status'; define gestation/format=term. group 'Gestation Period'; define race/format=race. group "Mother's Race"; define num/n 'Number of Cases'; define avg/mean noprint; define wt_lb/computed 'Mean Birth Weight (lb.)' format=8.2; break after race/skip; break after smoke/summarize ol skip suppress; compute wt_lb; run; wt_lb=avg/16;

13 Partial Result

14 More Advanced Example Using the crew dataset and the following report, suppose I want to add a column for raise, which is 5% for Flight Attendants, 7% for pilots: proc report data=stt592.crew nowd headline headskip; column jobcode location salary=number salary=meansal salary=stdsal; define jobcode/ 'Position' group width=10; define location/ group; define number/ n 'Number of obs.' width=6; define meansal/ mean 'Mean Salary' format=dollar12.2; define stdsal/ std 'Standard Deviation' format=dollar12.2; break after jobcode/summarize ol skip suppress; rbreak after/ summarize dol; run;

15 More Advanced Example Just like the data step, if-then-else logic is permissible, as are the functions that were useful before: proc report data=stt592.crew nowd headline headskip; column jobcode location salary=number salary=meansal salary=stdsal avgraise; define jobcode/ 'Position' group width=10; define location/ group; define number/ n 'Number of obs.' width=6; define meansal/ mean 'Mean Salary' format=dollar12.2; define stdsal/ std 'Standard Deviation' format=dollar12.2; define avgraise/ computed 'Mean Raise' format=dollar12.2; break after jobcode/summarize ol skip suppress; rbreak after/ summarize dol; compute avgraise; run; if substr(jobcode,1,1) eq 'F' then avgraise=0.05*meansal; else avgraise=0.07*meansal;

16 Result

17 Result Are these right?

18 Try this proc report data=stt592.crew nowd headline headskip; column jobcode location salary=number salary=meansal salary=stdsal; define jobcode/ 'Position' group width=10; define location/ group; define number/ n 'Number of obs.' width=6; define meansal/ mean 'Mean Salary' format=dollar12.2; define stdsal/ std 'Standard Deviation' format=dollar12.2; break after jobcode/summarize ol skip suppress; rbreak after/ summarize dol; compute avgraise; if substr(jobcode,1,1) eq 'F' then avgraise=0.05*meansal; else if substr(jobcode,1,1) eq P then avgraise=0.07*meansal; run; What s going on?

19 More Advanced Example I may need to be careful when working with group variables, particularly when they do not appear on all lines. proc report data=stt592.crew nowd headline headskip; column jobcode location salary=number salary=meansal salary=stdsal avgraise; define jobcode/ 'Position' group width=10; define location/ group; define number/ n 'Number of obs.' width=6; define meansal/ mean 'Mean Salary' format=dollar12.2; define stdsal/ std 'Standard Deviation' format=dollar12.2; define avgraise/ computed 'Mean Raise' format=dollar12.2; break after jobcode/summarize ol skip suppress; rbreak after/ summarize dol; compute avgraise; run; if substr(jobcode,1,1) eq 'F' then avgraise=0.05*meansal; else avgraise=0.07*meansal;

20 More Advanced Example I may need to be careful when working with group variables, particularly when they do not appear on all lines. I can track, sort of, using a data set: proc report data=stt592.crew nowd headline headskip out=check; column jobcode location salary=number salary=meansal salary=stdsal avgraise; define jobcode/ 'Position' group width=10; define location/ group; define number/ n 'Number of obs.' width=6; define meansal/ mean 'Mean Salary' format=dollar12.2; define stdsal/ std 'Standard Deviation' format=dollar12.2; define avgraise/ computed 'Mean Raise' format=dollar12.2; break after jobcode/summarize ol skip suppress; rbreak after/ summarize dol; compute avgraise; run; if substr(jobcode,1,1) eq 'F' then avgraise=0.05*meansal; else avgraise=0.07*meansal; This creates an output data set that tracks much of the REPORT process

21 Output Data Set

22 Output Data Set Still deceiving, these values are not all present when report is written.

23 More Advanced Example We need to establish a value for the job code group when (or before) we enter it that will remain consistent throughout, avoiding the skipping of the values. Compute blocks also allow us to use targets, much like break/rbreak statements to get values at certain locations within the report. If we use break lines of any type, report also tracks them with the _break_ variable (look back at the last data set)

24 More Advanced Example Improvement: proc report data=stt592.crew nowd headline headskip out=check; column jobcode location salary=number salary=meansal salary=stdsal avgraise; define jobcode/ 'Position' group width=10; define location/ group; define number/ n 'Number of obs.' width=6; define meansal/ mean 'Mean Salary' format=dollar12.2; define stdsal/ std 'Standard Deviation' format=dollar12.2; define avgraise/ computed 'Mean Raise' format=dollar12.2; break after jobcode/summarize ol skip suppress; rbreak after/ summarize dol; compute before jobcode; job=substr(jobcode,1,1); compute avgraise; if substr(jobcode,1,1) eq 'F' then avgraise=0.05*meansal; else avgraise=0.07*meansal; run;

25 More Advanced Example Improvement: proc report data=stt592.crew nowd headline headskip out=check; column jobcode location salary=number salary=meansal salary=stdsal avgraise; define jobcode/ 'Position' group width=10; define location/ group; define number/ n 'Number of obs.' width=6; define meansal/ mean 'Mean Salary' format=dollar12.2; define stdsal/ std 'Standard Deviation' format=dollar12.2; define avgraise/ computed 'Mean Raise' format=dollar12.2; break after jobcode/summarize ol skip suppress; rbreak after/ summarize dol; compute before jobcode; job=substr(jobcode,1,1); compute avgraise; run; if substr(jobcode,1,1) eq 'F' then avgraise=0.05*meansal; else avgraise=0.07*meansal; Compute the value I want to condition on at the top of the jobcode group

26 More Advanced Example Improvement: proc report data=stt592.crew nowd headline headskip out=check; column jobcode location salary=number salary=meansal salary=stdsal avgraise; define jobcode/ 'Position' group width=10; define location/ group; define number/ n 'Number of obs.' width=6; define meansal/ mean 'Mean Salary' format=dollar12.2; define stdsal/ std 'Standard Deviation' format=dollar12.2; define avgraise/ computed 'Mean Raise' format=dollar12.2; break after jobcode/summarize ol skip suppress; rbreak after/ summarize dol; compute before jobcode; job=substr(jobcode,1,1); compute avgraise; run; if job eq 'F' then avgraise=0.05*meansal; else avgraise=0.07*meansal; Now the value is consistent and useable for conditioning to compute the raise. Take a look at the output data set from this case

27 Result Did we get them all right?

28 Result This will take a bit of work