Hi everyone.
I have a data set and I attached it to my message. You can see it below.
I want to calculate bolt_volume. It looks simple but I couldn't get correct results. The formula has already written in excel sheet.
bolt_volume[row2] = ( bolt_area[row1] + bolt_area[row2] ) / 2 * bolt_len[row2]
bolt_volume[row3] = ( bolt_area[row2] + bolt_area[row3] ) / 2 * bolt_len[row3]
...........
tree_no | bolt_no | bolt_len | bolt_area | bolt_volume |
1 | 1.235344635 | |||
1 | 1 | 2 | 0.89358336 | 2.128927995 |
1 | 2 | 2 | 0.821784859 | 1.715368219 |
2 | 0.346877809 | |||
2 | 1 | 2 | 0.276875719 | 0.623753528 |
2 | 2 | 2 | 0.226900035 | 0.503775754 |
3 | 0.294638715 | |||
3 | 1 | 2 | 0.193085235 | 0.48772395 |
3 | 2 | 2 | 0.185057629 | 0.378142864 |
Thank you for your help.
Here is one way:
data want;
set have;
by tree_no;
bolt_volume=ifn(first.tree_no,.,lag(bolt_area)+bolt_area) / 2 * bolt_len;
run;
Hi,
This should work for the desired output.
Thanks,
Naeem
data want;
set have;
bolt_volume=(bolt_area+lag(bolt_area))/2*bolt_len;
run;
Here is one way:
data want;
set have;
by tree_no;
bolt_volume=ifn(first.tree_no,.,lag(bolt_area)+bolt_area) / 2 * bolt_len;
run;
Thanks stat@sas and Arthur Tabachneck ,
Both of your codes worked perfectly.
Just be careful with Naeem's code as it will give you non-missing, and wrong values, for the 1st record of the 2nd thru Nth by groups.
My original data set has more than 2000 observations. After I saw your message, I checked your codes and Nadeem's codes for my data set. But I couldn't see wrong values 1st record of the 2nd through Nth by groups.
I stand corrected! I hadn't noticed that bolt_len was always missing for your first record within an id. If that is the case in all situations, then Naeem's code will provide the correct result.
Thanks Arthur - Yes, if first id is not missing then your suggested solution is a definite choice.
Regards,
Naeem
Ok. I see now. That's tender spot.
Thanks Arthur.
An operator in SAS is a symbol which is used in a mathematical, logical or comparison expression.
Example Arithmetic Operators.
DATA MYDATA1;
input @1 COL1 4.2 @7 COL2 3.1;
Add_result = COL1+COL2;
Sub_result = COL1-COL2;
Mult_result = COL1*COL2;
Div_result = COL1/COL2;
Expo_result = COL1**COL2;
datalines;
11.21 5.3
3.11 11
;
PROC PRINT DATA=MYDATA1;
RUN;
On running the above code, we get the following output.
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