matrix() Function
Sometimes you may have only one vector that you need to convert into a matrix. How can it be done? The answer is simple - by using the matrix() function.
This function has the following parameters:
matrix(data = NA, nrow = 1, ncol = 1, byrow = F)
These are not all the parameters, but the most important for us.
data- is the vector that we want to use to build the matrix;nrow- number of rows in a new matrix;ncol- number of columns in a new matrix;byrow- logical, should the matrix be filled by rows. It's important to note that the length of the vector filled as thedataparameter must be divisible bynroworncol. If both parameters are set, thennrow*ncolmust equal the vector length.
For example, let's construct a 3x3 matrix with integers from 1 to 9.
# Vector of integers num <- 1:9 # Build a matrix from vector matrix(num, nrow = 3, ncol = 3)
As you can see, this matrix was built from above to below first. Let's set parameter byrow to T and compare the results.
num <- 1:9 # Build a matrix from vector by rows matrix(num, nrow = 3, ncol = 3, byrow = T)
As you can see, we filled this matrix from left to right. We were free to leave only one of the nrow or ncol parameters since 9 (number of elements in the vector) is divisible by 3 and returns an integer result.
Swipe to start coding
Given a vector of numbers named num.
2 4 6 8 10 12 14 16
Based on this vector, you need to build the following matrix.
2 4 6 810 12 14 16
Use only the matrix() function, and think about the correct values of parameters.
Рішення
How does seq() function work? seq(a, b) generates integers from a to b inclusive. seq(a, b, c) generates integers from a to b with the step c.
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