Let's break down what your code asked SAS to do.
First you have a data step to create a work dataset named NEWDATA.
SAS does not care that you forgot to add a space after the end of the variable name MAJ since $ is not a valid character to include in a variable name it was able to work out that you meant the variables NAME and MAJ to be defined a character instead of numeric. Since you did not set a length for NAME and MAJ it will default to length of $8. You also did not end the lines of data, but since you have a line with a semicolon on it SAS will use that as marking the end of the data and just ignore the other characters like "RUN" on the line.
A more complete data step might look like this instead:
data newdata;
length name $7 age 8 maj $10 score 8;
input name age maj score;
cards;
sara 25 nursing .9
kim 26 dance 1
charlie 21 psychology 4.3
anna 18 dance .45
;
You then tried to run another data step to replace NEWDATA with a new dataset with same name. That step will read from a dataset name NEWDATA_2 that you never defined before. Does NEWDATA_2 exist? Does it have the same variables as NEWDATA?
Perhaps you meant instead to create NEWDATA_2 by reading in NEWDATA?
data newdata_2;
set newdata;
The rest of the data step appears to be an attempt to write IF/THEN statements.
Let's look at the last 3 first since they at least look like valid SYNTAX.
if score <1 then newscore = low;
if score <=1 then newscore = mid;
if score <=3 then newscore = high;
So when SCORE is less than 1 you set NEWSCORE to the value LOW. But there is no variable named LOW in the NEWDATA dataset. So SAS will create a new variable and default its value to missing. Similarly for the variables MID and HIGH.
Did you want variable NEWSCORE to be character? If so you should first define it as such. What length will it need to store the longest possible value? Perhaps only 4 bytes to store 'high'?
length newscore $4;
if score <1 then newscore = 'low';
if score <=1 then newscore = 'mid';
if score <=3 then newscore = 'high';
Now we need to look a the logic error of these three statements when taken together. If SCORE is less then 1 then NEWSCORE is set to 'low' by the first IF/THEN. It will then be set to 'mid' by the second and finally it will be set to 'high' by the last.
You should probably use some ELSE statements in there so that when one test succeeds the other tests are skipped.
if score <1 then newscore = 'low';
else if score <=1 then newscore = 'mid';
else if score <=3 then newscore = 'high';
Now the only logic errors are what to do with missing values of SCORE. With this code those will cause NEWSORE to be set to 'low' since a missing value is smaller than any actual number. And what about values of SCORE that are larger than 3? Currently for those the value of NEWSCORE will be blank since none of the conditions will be true.
Perhaps you meant that values larger than 3 should by HIGH (your example data has a value of 4.3). In that case you might want to do something like this instead.
if score >3 then newscore = 'high';
else if score >= 1 then newscore = 'mid';
else if score >= 0 then newscore = 'low';
Now values larger than 3 will have NEWSCORE='high' and values from 1 to 3, inclusive, will ahve NEWSCORE='mid' and values from zero to less than 1 will have newscore = 'low' and missing values and negative values will have newscore=' '.
Now back to the other two IF / THEN statements.
if maj nursing psychology then newmaj = sci;
if maj dance then newmajo = art;
These are invalid syntax since you cannot have two or three variables listed in a row without operators between them.
I suspect that you only wanted MAJ to be a variable reference and the others to string literals so as to test if the value of MAJ is one of those other strings. You can use the IN operator for lists of one or more values. And if the list is only one value you can use the = (equality test) operator.
Also do you want to create two different new variables? NEWMAJ and NEWMAJO ? Or just one? And again how long should it be defined to store the longest value it will need to hold?
length newmaj $3 ;
if maj in ('nursing' 'psychology') then newmaj = 'sci';
else if maj='dance' then newmaj = 'art';
The RUN; statement looks right. Since there is no in-line data to end the code for the data step adding a RUN will let SAS (and other programmers reading your code) that you have finished defining the data step.
