Find the maximum and minimum value of every column and then find the maximum and minimum value of every row

r matrix max minimum
Kostas Dimakis picture Kostas Dimakis · Nov 12, 2014 · Viewed 71.8k times · Source

I've got this matrix:

a <- matrix(rnorm(1000 * 18, mean = 100, sd = sqrt(10)), 1000, 18)

I would like to find the maximum and minimum value of every column and the maximum and minimum value of every row.

Answer

Kostas Dimakis picture Kostas Dimakis · Nov 12, 2014

Figured it out.

Minimum and maximum of every column:

apply(a,2,min)
apply(a,2,max)

Minimum and maximum of every row:

apply(a,1,min)
apply(a,1,max)

Found the information here http://www.personality-project.org/r/r.commands.html

Related questions

R memory management / cannot allocate vector of size n Mb

I am running into issues trying to use large objects in R. For example: > memory.limit(4000) > a = matrix(NA, 1500000, 60) > a = matrix(NA, 2500000, 60) > a = matrix(NA, 3500000, 60) Error: cannot allocate vector of size 801.1 Mb > a = matrix(NA, 2500000, 60) …

Read More
Subscript out of bounds - general definition and solution?

When working with R I frequently get the error message "subscript out of bounds". For example: # Load necessary libraries and data library(igraph) library(NetData) data(kracknets, package = "NetData") # Reduce dataset to nonzero edges krack_full_nonzero_edges <- …

Read More
Select rows of a matrix that meet a condition

In R with a matrix: one two three four [1,] 1 6 11 16 [2,] 2 7 12 17 [3,] 3 8 11 18 [4,] 4 9 11 19 [5,] 5 10 15 20 I want to extract the submatrix whose rows have column three = 11. That is: one two three four [1,] 1 6 11 16 [3,] 3 8 11 18 [4,] 4 9 11 19 I want to do this without looping. I am new to R so this …

Read More