SAS and line pointers in a loop - sas

Question

data test;
infile datalines;
input k1 k2 k3 k4 k5 k6 k7 k8 k9 k10;
array a(*) k1-k10;
do i=1 to 10;
if a(i) eq . then stop;
line=a(i);
input #line k1 k2 k3 k4 k5 k6 k7 k8 k9 k10;
output;
end;
stop;
datalines;
5 9 2 4 6 3 . . . .
29 57 32 9 2 29 2 0 23 1
83 34 28 1 43 3 24 2 6 2
0 84 62 75 3 52 65 1 5 2
0 2 12 45 92 3 60 24 6 2
47 24 87 2 52 36 1 17 3 1
90 93 2 1 40 20 75 2 5 14
78 27 27 2 4 1 12 21 4 2
21 40 3 21 3 19 3 2 4 2
84 2 5 3 13 6 23 98 1 2
;
run;
I want to read only the observations whose numbers are in the first row. The expected result:
0 2 12 45 92 3 60 24 6 2
21 40 3 21 3 19 3 2 4 2
29 57 32 9 2 29 2 0 23 1
0 84 62 75 3 52 65 1 5 2
47 24 87 2 52 36 1 17 3 1
83 34 28 1 43 3 24 2 6 2
The error I get after running my code:
ERROR: Old line 3387 wanted but SAS is at line 3391.
Use: INFILE N=X; , with a suitable value of x.
RULE: ----+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0
3391 47 24 87 2 52 36 1 17 3 1
k1=0 k2=2 k3=12 k4=45 k5=92 k6=3 k7=60 k8=24 k9=6 k10=2 i=2 line=2 _ERROR_=1 _N_=1
What does "a suitable value of x" mean? What should I change in my code?

Answer 1

You are overwriting the values in your array with your second input statement. Here they are read into different variables so as not to be overwritten.
data test;
infile datalines n=100;
input h1 h2 h3 h4 h5 h6 h7 h8 h9 h10;
array h{*} h1-h10;
do i = 1 to 10;
line = h[i];
if line then do;
input #line k1 k2 k3 k4 k5 k6 k7 k8 k9 k10;
output;
end;
end;
keep k:;
datalines;
5 9 2 4 6 3 . . . .
29 57 32 9 2 29 2 0 23 1
83 34 28 1 43 3 24 2 6 2
0 84 62 75 3 52 65 1 5 2
0 2 12 45 92 3 60 24 6 2
47 24 87 2 52 36 1 17 3 1
90 93 2 1 40 20 75 2 5 14
78 27 27 2 4 1 12 21 4 2
21 40 3 21 3 19 3 2 4 2
84 2 5 3 13 6 23 98 1 2
;
run;

Answer 2

SAS is telling you that you need to amend your infile statement to allow it to read a sufficient number of lines ahead. For your code as written, n=10 should be ok, as none of variables you're using to get the line number have values greater than 10.
data test;
/*Add the n= option to the infile statement as suggested by log message*/
infile datalines n= 10;
input k1 k2 k3 k4 k5 k6 k7 k8 k9 k10;
array a(*) k1-k10;
array b(*) b1-b10;
/*Make a copy of the first row
that won't get overwritten by subsequent input statements*/
do i=1 to 10;
b(i) = a(i);
end;
do i=1 to 10;
if b(i) eq . then stop;
line=b(i);
input #line k1 k2 k3 k4 k5 k6 k7 k8 k9 k10;
output;
end;
stop;
datalines;
5 9 2 4 6 3 . . . .
29 57 32 9 2 29 2 0 23 1
83 34 28 1 43 3 24 2 6 2
0 84 62 75 3 52 65 1 5 2
0 2 12 45 92 3 60 24 6 2
47 24 87 2 52 36 1 17 3 1
90 93 2 1 40 20 75 2 5 14
78 27 27 2 4 1 12 21 4 2
21 40 3 21 3 19 3 2 4 2
84 2 5 3 13 6 23 98 1 2
;
run;