Is it possible to make a new statistic with proc summary that multiplies every value in each column, for example instead of just mean? SAS is so rigid it makes me crazy.
data test;
input b c ;
datalines;
50 11
35 12
75 13
;
Desired output would be 50*35*75, and 11*12*13, and _FREQ (as is normal output in proc summary)
This is an uncommon aggregate so you essentially need to roll your own. Since a data step loops this is easily accomplished using a RETAIN to keep value from row to row and outputting result at the last record.
Data want;
Set have end=eof;
Retain prod_b prod_c;
prod_b = prod_b * b;
prod_c = prod_c * c;
Freq= _n_;
If eof then OUTPUT;
Keep prod: freq;
Run;
Related
I can't find a way to summarize the same variable using different weights.
I try to explain it with an example (of 3 records):
data pippo;
a=10;
wgt1=0.5;
wgt2=1;
wgt3=0;
output;
a=3;
wgt1=0;
wgt2=0;
wgt3=1;
output;
a=8.9;
wgt1=1.2;
wgt2=0.3;
wgt3=0.1;
output;
run;
I tried the following:
proc summary data=pippo missing nway;
var a /weight=wgt1;
var a /weight=wgt2;
var a /weight=wgt3;
output out=pluto (drop=_freq_ _type_) sum()=;
run;
Obviously it gives me a warning because I used the same variable "a" (I can't rename it!).
I've to save a huge amount of data and not so much physical space and I should construct like 120 field (a0-a6,b0-b6 etc) that are the same variables just with fixed weight (wgt0-wgt5).
I want to store a dataset with 20 columns (a,b,c..) and 6 weight (wgt0-wgt5) and, on demand, processing a "summary" without an intermediate datastep that oblige me to create 120 fields.
Due to the huge amount of data (more or less 55Gb every month) I'd like also not to use proc sql statement:
proc sql;
create table pluto
as select sum(db.a * wgt1) as a0, sum(db.a * wgt1) as a1 , etc.
quit;
There is a "Super proc summary" that can summarize the same field with different weights?
Thanks in advance,
Paolo
I think there are a few options. One is the data step view that data_null_ mentions. Another is just running the proc summary however many times you have weights, and either using ods output with the persist=proc or 20 output datasets and then setting them together.
A third option, though, is to roll your own summarization. This is advantageous in that it only sees the data once - so it's faster. It's disadvantageous in that there's a bit of work involved and it's more complicated.
Here's an example of doing this with sashelp.baseball. In your actual case you'll want to use code to generate the array reference for the variables, and possibly for the weights, if they're not easily creatable using a variable list or similar. This assumes you have no CLASS variable, but it's easy to add that into the key if you do have a single (set of) class variable(s) that you want NWAY combinations of only.
data test;
set sashelp.baseball;
array w[5];
do _i = 1 to dim(w);
w[_i] = rand('Uniform')*100+50;
end;
output;
run;
data want;
set test end=eof;
i = .;
length varname $32;
sumval = 0 ;
sum=0;
if _n_ eq 1 then do;
declare hash h_summary(suminc:'sumval',keysum:'sum',ordered:'a');;
h_summary.defineKey('i','varname'); *also would use any CLASS variable in the key;
h_summary.defineData('i','varname'); *also would include any CLASS variable in the key;
h_summary.defineDone();
end;
array w[5]; *if weights are not named in easy fashion like this generate this with code;
array vars[*] nHits nHome nRuns; *generate this with code for the real dataset;
do i = 1 to dim(w);
do j = 1 to dim(vars);
varname = vname(vars[j]);
sumval = vars[j]*w[i];
rc = h_summary.ref();
if i=1 then put varname= sumval= vars[j]= w[i]=;
end;
end;
if eof then do;
rc = h_summary.output(dataset:'summary_output');
end;
run;
One other thing to mention though... if you're doing this because you're doing something like jackknife variance estimation or that sort of thing, or anything that uses replicate weights, consider using PROC SURVEYMEANS which can handle replicate weights for you.
You can SCORE your data set using a customized SCORE data set that you can generate
with a data step.
options center=0;
data pippo;
retain a 10 b 1.75 c 5 d 3 e 32;
run;
data score;
if 0 then set pippo;
array v[*] _numeric_;
retain _TYPE_ 'SCORE';
length _name_ $32;
array wt[3] _temporary_ (.5 1 .333);
do i = 1 to dim(v);
call missing(of v[*]);
do j = 1 to dim(wt);
_name_ = catx('_',vname(v[i]),'WGT',j);
v[i] = wt[j];
output;
end;
end;
drop i j;
run;
proc print;[enter image description here][1]
run;
proc score data=pippo score=score;
id a--e;
var a--e;
run;
proc print;
run;
proc means stackods sum;
ods exclude summary;
ods output summary=summary;
run;
proc print;
run;
enter image description here
Ive got 50 columns of data, with 4 different measurements in each, as well as designation tags (groups C, D, and E). Ive averaged the 4 measurements... So every data point now has an average. Now, I am supposed to take the average of all the data points averages of each specific group.
So I want all the data in group C to be averaged, and so on for D and E.... and I dont know how to do that.
avg1=(MEAS1+MEAS2+MEAS3+MEAS4)/4;
avg_score=round(avg1, .1);
run;
proc print;
run;
This is what I have so far.
There are several procedures, and SQL that can average values over a group.
I'll guess you meant to say 50 rows of data.
Example:
Proc MEANS
data have;
call streaminit(314159);
do _n_ = 1 to 50;
group = substr('CDE', rand('integer',3),1);
array v meas1-meas4;
do _i_ = 1 to dim(v);
num + 2;
v(_i_) = num;
end;
output;
end;
drop num;
run;
data rowwise_means;
set have;
avg_meas = mean (of meas:);
run;
* group wise means of row means;
proc means noprint data=rowwise_means nway;
class group;
var avg_meas;
output out=want mean=meas_grandmean;
run;
rowwise_means
want (grandmean, or mean of means)
I would like to turn the following long dataset:
data test;
input Id Injury $;
datalines;
1 Ankle
1 Shoulder
2 Ankle
2 Head
3 Head
3 Shoulder
;
run;
Into a wide dataset that looks like this:
ID Ankle Shoulder Head
1 1 1 0
2 1 0 1
3 0 1 1'
This answer seemed the most relevant but was falling over at the proc freq stage (my real dataset is around 1 million records, and has around 30 injury types):
Creating dummy variables from multiple strings in the same row
Additional help: https://communities.sas.com/t5/SAS-Statistical-Procedures/Possible-to-create-dummy-variables-with-proc-transpose/td-p/235140
Thanks for the help!
Here's a basic method that should work easily, even with several million records.
First you sort the data, then add in a count to create the 1 variable. Next you use PROC TRANSPOSE to flip the data from long to wide. Then fill in the missing values with a 0. This is a fully dynamic method, it doesn't matter how many different Injury types you have or how many records per person. There are other methods that are probably shorter code, but I think this is simple and easy to understand and modify if required.
data test;
input Id Injury $;
datalines;
1 Ankle
1 Shoulder
2 Ankle
2 Head
3 Head
3 Shoulder
;
run;
proc sort data=test;
by id injury;
run;
data test2;
set test;
count=1;
run;
proc transpose data=test2 out=want prefix=Injury_;
by id;
var count;
id injury;
idlabel injury;
run;
data want;
set want;
array inj(*) injury_:;
do i=1 to dim(inj);
if inj(i)=. then inj(i) = 0;
end;
drop _name_ i;
run;
Here's a solution involving only two steps... Just make sure your data is sorted by id first (the injury column doesn't need to be sorted).
First, create a macro variable containing the list of injuries
proc sql noprint;
select distinct injury
into :injuries separated by " "
from have
order by injury;
quit;
Then, let RETAIN do the magic -- no transposition needed!
data want(drop=i injury);
set have;
by id;
format &injuries 1.;
retain &injuries;
array injuries(*) &injuries;
if first.id then do i = 1 to dim(injuries);
injuries(i) = 0;
end;
do i = 1 to dim(injuries);
if injury = scan("&injuries",i) then injuries(i) = 1;
end;
if last.id then output;
run;
EDIT
Following OP's question in the comments, here's how we could use codes and labels for injuries. It could be done directly in the last data step with a label statement, but to minimize hard-coding, I'll assume the labels are entered into a sas dataset.
1 - Define Labels:
data myLabels;
infile datalines dlm="|" truncover;
informat injury $12. labl $24.;
input injury labl;
datalines;
S460|Acute meniscal tear, medial
S520|Head trauma
;
2 - Add a new query to the existing proc sql step to prepare the label assignment.
proc sql noprint;
/* Existing query */
select distinct injury
into :injuries separated by " "
from have
order by injury;
/* New query */
select catx("=",injury,quote(trim(labl)))
into :labls separated by " "
from myLabels;
quit;
3 - Then, at the end of the data want step, just add a label statement.
data want(drop=i injury);
set have;
by id;
/* ...same as before... */
* Add labels;
label &labls;
run;
And that should do it!
I have a dataset looks like the following:
Name Number
a 1
b 2
c 9
d 6
e 5.5
Total ???
I want to calculate the sum of variable Number and record the sum in the last row (corresponding with Name = 'total'). I know I can do this using proc means then merge the output backto this file. But this seems not very efficient. Can anyone tell me whether there is any better way please.
you can do the following in a dataset:
data test2;
drop sum;
set test end = last;
retain sum;
if _n_ = 1 then sum = 0;
sum = sum + number;
output;
if last then do;
NAME = 'TOTAL';
number = sum;
output;
end;
run;
it takes just one pass through the dataset
It is easy to get by report procedure.
data have;
input Name $ Number ;
cards;
a 1
b 2
c 9
d 6
e 5.5
;
proc report data=have out=want(drop=_:);
rbreak after/ summarize ;
compute after;
name='Total';
endcomp;
run;
The following code uses the DOW-Loop (DO-Whitlock) to achieve the result by reading through the observations once, outputting each one, then lastly outputting the total:
data want(drop=tot);
do until(lastrec);
set have end=lastrec;
tot+number;
output;
end;
name='Total';
number=tot;
output;
run;
For all of the data step solutions offered, it is important to keep in mind the 'Length' factor. Make sure it will accommodate both 'Total' and original values.
proc sql;
select max(5,length) into :len trimmed from dictionary.columns WHERE LIBNAME='WORK' AND MEMNAME='TEST' AND UPCASE(NAME)='NAME';
QUIT;
data test2;
length name $ &len;
set test end=last;
...
run;
Say we have the SAS code:
data t1 (keep=KEY COUNT C_AMT2 C_AMT);
SET t1;
BY key;
RETAIN COUNT C_AMT;
IF FIRST.KEY THEN
DO;
COUNT=0;
C_AMT2=0;
END;
COUNT+1;
C_AMT=SUM(C_AMT2, C_AMT);
IF LAST.KEY THEN
OUTPUT;
RUN;
What would change here if I were to remove "IF LAST.KEY THEN OUTPUT;". The documentation says that output causes SAS to write to the datastep immediately, not at the end of the data step. Because here it is right before the end of the data step, would this mean removing it would cause no difference?
Removing it would cause a difference.
Then you would have a record for every value of key, assuming multiple values. Controlling the output means you'd have only the last record.
It looks like it's calculating a count and total so there are other ways to achieve this. I'm going to assume that there's some other code that you've suppressed.
The relevant section from the documentation that refers to this is in the link you have above
Implicit versus Explicit Output
By default, every DATA step contains an implicit OUTPUT statement at the end of each iteration that tells SAS to write observations to the data set or data sets that are being created. Placing an explicit OUTPUT statement in a DATA step overrides the automatic output, and SAS adds an observation to a data set only when an explicit OUTPUT statement is executed. Once you use an OUTPUT statement to write an observation to any one data set, however, there is no implicit OUTPUT statement at the end of the DATA step. In this situation, a DATA step writes an observation to a data set only when an explicit OUTPUT executes. You can use the OUTPUT statement alone or as part of an IF-THEN or SELECT statement or in DO-loop processing.
Here's some code that simulates your issue:
*Generate random data;
Data have;
do Key=1 to 2;
do i=1 to 3;
Amount=floor(rand('normal', 50, 5));
OUTPUT;
end;
end;
run;
data t1;
set have;
retain count C_Amt;
by Key;
if first.key then do;
count=0;
C_Amt=0;
end;
Count+1;
c_amt=sum(c_amt, amount);
if last.key then output;
run;
proc print data=t1;
run;
data t1;
set have;
retain count C_Amt;
by Key;
if first.key then do;
count=0;
C_Amt=0;
end;
Count+1;
c_amt=sum(c_amt, amount);
*if last.key then output;
run;
proc print data=t1;
run;
And the corresponding output:
With last.key then output
Obs Key i Amount count C_Amt
1 1 3 46 3 147
2 2 3 44 3 154
And with out last.key
Obs Key i Amount count C_Amt
1 1 1 47 1 47
2 1 2 54 2 101
3 1 3 46 3 147
4 2 1 61 1 61
5 2 2 49 2 110
6 2 3 44 3 154
Commas are an error here:
(keep=KEY, COUNT, C_AMT2, C_AMT)
Anyway:
RUN;
usually means:
output;
return;
But if SAS encounters an output statement in your code, the output at the end (enclosed in the run statement) will be ignored.
Hence, since your output statement is conditionally executed only IF LAST.KEY, in your dataset you will have only observations marked as last.key, because your RUN; will only mean return.
Something like:
data want; set have; output; run;
Is exactly the same to not explicit output:
data want; set have; output; run;
You can use output as you want:
data want01 want02;
set have;
if a then output want01;
if b then output want02;
run;
data want01;
var=var1;
output;
var=var2;
output;
run;