Feature #10445
closed
[PATCH 3/3] Extend Matrix#[]
Description
I've made patches which Matrix#[] returns new vector if either arguments is range,
and returns new matrix, if both arguments are range.
Like below.
# matrix[row, column] -> obj or nil # matrix[row, col_range] -> new_vector or nil # matrix[row_range, column] -> new_vector or nil # matrix[row_range, col_range] -> new_matrix or nil Matrix.diagonal(9, 5, -3)[1, 1] => 5 Matrix.diagonal(9, 5, -3)[1, 0..1] => Vector[0, 5] Matrix.diagonal(9, 5, -3)[0..1, 0] => Vector[9, 0] Matrix.diagonal(9, 5, -3)[0..1, 0..1] => Matrix[[9, 0], [0, 5]] I'm not sure matrix[row, col_range] should return vector or matrix
But from my view, it's fine.
I'm not in a hurry. Take your time.
Files
Updated by marcandre (Marc-Andre Lafortune) almost 11 years ago
- Status changed from Open to Feedback
I understand the idea, but I'm not convinced.
Currently, [] is a simple access to the elements of a matrix. This proposal makes it more complex and changes completely the type of return depending on the arguments. The main question is: when would someone want to extract a minor from a matrix and much prefer calling [] instead of the clearer and explicit minor?
I feel like we should favor explicitness in this case.
Updated by gogotanaka (Kazuki Tanaka) almost 11 years ago
@Marc-Andre Lafortune
Thank you for reply.
OK, the answer is when we expect Matrix to behave something like Array, I mean..
[1,2,3,4][1..2] #=> [2,3] Matrix[[1,2,3],[4,5,6],[7,8,9]][0..1, 0..1] #=> Matrix[[1,2], [4,5]] Actually I am also one of people who expect such a behavior.
Thanks.
Updated by marcandre (Marc-Andre Lafortune) almost 5 years ago
- Status changed from Feedback to Rejected
Closing this, mainly for performance reason; best use Matrix#minor.