ifirstNot
Syntax
ifirstNot(X)
Arguments
X is a vector, or a tuple of vectors of equal length, or a matrix.
Details
If X is a vector, return the subscript of the first non-NULL element. Return -1 if all elements are NULL.
If X is a tuple of vectors, return the subscript of the first position where the element in all vectors is not NULL.
If X is a matrix, return the subscript of the first non-NULL element within each column. The result is a vector.
Examples
ifirstNot(NULL NULL 2 4 8 NULL 1);
// output
2
ifirstNot(take(int(),5));
// output
-1
x=NULL NULL 4 7 8 NULL
y=1 NULL NULL 4 NULL NULL
ifirstNot([x,y]);
// output
3
x=NULL NULL 4 7 8 NULL
y=1 2 NULL NULL NULL 6
ifirstNot([x,y]);
// output
-1
m=matrix(0 NULL 1 2 3, NULL 2 NULL 0 3);
m;| #0 | #1 |
|---|---|
| 0 | |
| 2 | |
| 1 | |
| 2 | 0 |
| 3 | 3 |
ifirstNot(m);
// output
[0,1]