Hello,
Consider the following program;
data have;
input a;
cards;
1
2
;
run;
proc sort data=sashelp.class out=class;
by sex;
run;
data test;
set have;
do i=1 to nobs;
set class nobs=nobs;
by sex;
if first.sex then total_weight=0;
total_weight+weight;
output;
end;
run;
When execution reaches observation 2 of the have dataset, the whole sashelp.class has already been entirely read.
Thus the consecutive "set sashelp.class" will stop the data step.
I can not use the point= option because of by group processing.
Thanks for any advice to overcome this difficulty.
For the more complex problem, I confess to not reading it through sufficiently. But it should still be possible to use POINT= to read every observation without a BY statement. You would need to set up multiple buckets for the calculations (analogous to one set of calculations for F and one for M) when looping through with POINT=.
Sorry for not being clear enough. Here is what the resulting dataset should look like :
a | i | Name | Sex | Age | Height | Weight | total_weight |
1 | 1 | Alice | F | 13 | 56.5 | 84.0 | 84.0 |
1 | 2 | Barbara | F | 13 | 65.3 | 98.0 | 182.0 |
1 | 3 | Carol | F | 14 | 62.8 | 102.5 | 284.5 |
1 | 4 | Jane | F | 12 | 59.8 | 84.5 | 369.0 |
1 | 5 | Janet | F | 15 | 62.5 | 112.5 | 481.5 |
1 | 6 | Joyce | F | 11 | 51.3 | 50.5 | 532.0 |
1 | 7 | Judy | F | 14 | 64.3 | 90.0 | 622.0 |
1 | 8 | Louise | F | 12 | 56.3 | 77.0 | 699.0 |
1 | 9 | Mary | F | 15 | 66.5 | 112.0 | 811.0 |
1 | 10 | Alfred | M | 14 | 69.0 | 112.5 | 112.5 |
1 | 11 | Henry | M | 14 | 63.5 | 102.5 | 215.0 |
1 | 12 | James | M | 12 | 57.3 | 83.0 | 298.0 |
1 | 13 | Jeffrey | M | 13 | 62.5 | 84.0 | 382.0 |
1 | 14 | John | M | 12 | 59.0 | 99.5 | 481.5 |
1 | 15 | Philip | M | 16 | 72.0 | 150.0 | 631.5 |
1 | 16 | Robert | M | 12 | 64.8 | 128.0 | 759.5 |
1 | 17 | Ronald | M | 15 | 67.0 | 133.0 | 892.5 |
1 | 18 | Thomas | M | 11 | 57.5 | 85.0 | 977.5 |
1 | 19 | William | M | 15 | 66.5 | 112.0 | 1089.5 |
2 | 1 | Alice | F | 13 | 56.5 | 84.0 | 84.0 |
2 | 2 | Barbara | F | 13 | 65.3 | 98.0 | 182.0 |
2 | 3 | Carol | F | 14 | 62.8 | 102.5 | 284.5 |
2 | 4 | Jane | F | 12 | 59.8 | 84.5 | 369.0 |
2 | 5 | Janet | F | 15 | 62.5 | 112.5 | 481.5 |
2 | 6 | Joyce | F | 11 | 51.3 | 50.5 | 532.0 |
2 | 7 | Judy | F | 14 | 64.3 | 90.0 | 622.0 |
2 | 8 | Louise | F | 12 | 56.3 | 77.0 | 699.0 |
2 | 9 | Mary | F | 15 | 66.5 | 112.0 | 811.0 |
2 | 10 | Alfred | M | 14 | 69.0 | 112.5 | 112.5 |
2 | 11 | Henry | M | 14 | 63.5 | 102.5 | 215.0 |
2 | 12 | James | M | 12 | 57.3 | 83.0 | 298.0 |
2 | 13 | Jeffrey | M | 13 | 62.5 | 84.0 | 382.0 |
2 | 14 | John | M | 12 | 59.0 | 99.5 | 481.5 |
2 | 15 | Philip | M | 16 | 72.0 | 150.0 | 631.5 |
2 | 16 | Robert | M | 12 | 64.8 | 128.0 | 759.5 |
2 | 17 | Ronald | M | 15 | 67.0 | 133.0 | 892.5 |
2 | 18 | Thomas | M | 11 | 57.5 | 85.0 | 977.5 |
2 | 19 | William | M | 15 | 66.5 | 112.0 | 1089.5 |
proc sort data=sashelp.class out=class;
by sex;
run;
data class;
i = _n_;
set class nobs=nobs;
by sex;
if first.sex then total_weight=0;
total_weight+weight;
run;
proc surveyselect noprint rep=2 rate=1 out=stacked(rename=(replicate=a));
run;
Thanks @data_null__ and @Astounding for your answers. I tried to simplify the problem in order to avoid distracting readers with unnecessary details but i realize that it can give a misleading view of what i am trying to do.
The computation of sums only served as an example to justify a by statement. Actually, what is done in
the loop is dependant on the data in the currently processed row of the have dataset. That is,
for each row in have, i want to read the whole other dataset and create new variables that depend
on both datasets columns.
I just don't figure out how to restart reading the second dataset from observation 1 for each
new observation of the have dataset.
If you want the full context, i was trying to generalize my last answer in the following thread :
https://communities.sas.com/t5/SAS-Programming/Pairwise-comparisons-in-loops/m-p/497468#M131862
in order to take different sectors/quarters into account and stumbled upon this difficulty.
It should be easy enough to summarize SASHELP.CLASS down to 2 observations (M and F) before bringing in HAVE. Then you could use POINT= (or possibly a sort and merge if that is a better choice).
For the more complex problem, I confess to not reading it through sufficiently. But it should still be possible to use POINT= to read every observation without a BY statement. You would need to set up multiple buckets for the calculations (analogous to one set of calculations for F and one for M) when looping through with POINT=.
Thanks, i finally managed to overcome the difficulty. I needed in particular first.var and last.var created by the by statement so i used a prior data step to save them as new columns of the dataset. The by statement thus became useless and i could use the POINT= option.
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