问题
I have a 10 by 10 matrix. I want to form a sub-matrix from this main matrix, using all the rows and columns except the 1st, 2nd and 8th columns and rows.
I know Part can be used to form the sub-matrix, but the examples are mostly about forming the sub-matrix using consecutive rows and columns only.
回答1:
If this is your matrix:
tst = RandomInteger[10, {10, 10}];
This will do the trick for the case at hand:
tst[[{3, 4, 5, 6, 7, 9, 10}, {3, 4, 5, 6, 7, 9, 10}]]
Instead of explicit list, you could use Complement[Range[10],{1,2,8}]
.
回答2:
Here's another way.
Call your matrix
test = Array[m, {10, 10}]
Then your sub matrix is
subTest = Nest[Delete[Transpose[#], {{1}, {2}, {8}}] &, test, 2]
Compare with Leonid's method
subTest == test[[#, #]] &[Complement[Range[10], {1, 2, 8}]]
(* True *)
来源:https://stackoverflow.com/questions/6258349/how-to-form-submatrices-with-some-non-consecutive-rows-and-columns-of-a-matrix