matrix-nth ( pair matrix -- elt )
Matrix operations
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Vocabulary
math.matrices

Inputs
paira pair
matrixa matrix


Outputs
eltan object


Word description
Retrieve the element in the matrix at the zero-indexed row, column pair.

Notes
• This word is the two-dimensional variant of nth.
• This word is intended for use with "flat" (2-dimensional) matrices.


Errors
• bounds-error if the first element in pair is greater than the maximum row index in matrix
• bounds-error if the second element in pair is greater than the maximum column index in matrix


Examples
Get the entry at row 1, column 0.
USING: math.matrices prettyprint ; { 1 0 } { { 0 1 } { 2 3 } } matrix-nth .
2


Definition
USING: kernel sequences ;

IN: math.matrices

: matrix-nth ( pair matrix -- elt )
[ first2 swap ] dip nth nth ; inline