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

Question

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 v

Answer 1

You can try

apply(a, 1, range)

Using this together with t, this gives you two columns. The first one with the minimum the second with the maximum of the rows.

head(t(apply(a, 1, range)))
         [,1]     [,2]
[1,] 95.75922 103.6956
[2,] 93.62636 106.3934
[3,] 92.70567 106.9190
[4,] 96.53577 104.4971
[5,] 96.61573 107.6691
[6,] 95.56239 105.5887

for the column maxima change 1 to 2 in the apply function.