The RSUBSTR function returns an 
matrix with substrings of the input matrix with new strings.
The inputs to the RSUBSTR subroutine are as follows:
- x
-
is any
character matrix.
- p
-
is an
matrix or a scalar that determines the starting positions for substrings to be replaced.
- l
-
is an
matrix or a scalar that determines the lengths of substrings to be replaced.
- r
-
is an
matrix or a scalar that specifies the replacement strings.
If 
is zero, the replacement string in 
is simply inserted into the input matrix 
at the position indicated by 
.
For example, the following statements replace the first two characters of each entry in the matrix X with the corresponding entry in the matrix R:
x = {abc def ghi,jkl mno pqr};
r = {z y x, w v u};
p = 1;
l = 2;
c=rsubstr(x,p,l,r);
print x, c;