Subset a matrix according to a columns vector

by

Try 

H[cbind(seq_len(nrow(H)), P)]
## [1] 0.6733731 0.7396847 0.5953580

Here we are indexing by consecutive rows and columns indicated in P

Regarding your question, so the reason H[, P] returns a matrix is because you are telling R:

select all rows in columns: 2, 1, 2 from matrix “H”

thus the result that you are getting is a matrix with identical first and third columns.

More Related Contents:

  1. Matrix operation in R: I have a square matrix whose determinant is zero, i need to find its inverse in R programing. Is it possible ,if yes how? [closed]
  2. Loop through a R matrix row-wise and print elements [duplicate]
  3. Convert an upper to lower triangle matrix in r [duplicate]
  4. R memory management / cannot allocate vector of size n Mb
  5. Reshape three column data frame to matrix (“long” to “wide” format) [duplicate]
  6. How to subset matrix to one column, maintain matrix data type, maintain row/column names?
  7. Multiply rows of matrix by vector?
  8. All Levels of a Factor in a Model Matrix in R
  9. How to divide each row of a matrix by elements of a vector in R
  10. Subscript out of bounds – general definition and solution?
  11. Apply a function to every row of a matrix or a data frame
  12. Rotate a Matrix in R by 90 degrees clockwise
  13. Create dataframe from a matrix
  14. Get row and column indices of matches using `which()`
  15. Finding row index containing maximum value using R
  16. Function to split a matrix into sub-matrices in R
  17. Loop in R: how to save the outputs?
  18. R: Plotting a 3D surface from x, y, z
  19. Last Observation Carried Forward In a data frame? [duplicate]
  20. Directly creating dummy variable set in a sparse matrix in R
  21. Should I use a data.frame or a matrix?
  22. Find K nearest neighbors, starting from a distance matrix
  23. Select rows of a matrix that meet a condition
  24. R: How to rescale my matrix by column
  25. Calculate Euclidean distance matrix using a big.matrix object
  26. Appending a list to a list of lists in R
  27. Sum a list of matrices [duplicate]
  28. How to remove rows of a matrix by row name, rather than numerical index?
  29. fast large matrix multiplication in R
  30. R: Calculate cosine distance from a term-document matrix with tm and proxy

Leave a Comment