Matrix

A matrix is a vector represented and accessible in two dimensions. Therefore, what applies to vectors is most likely to apply to a matrix. For example, each type of vector (for example, numeric vector or logical vectors) has its matrix version, that is, there are numeric matrices, logical matrices, and so on.

Creating a matrix

We can call matrix() to create a matrix from a vector by setting up one of its two dimensions:

matrix(c(1, 2, 3, 2, 3, 4, 3, 4, 5), ncol = 3)
##      [,1] [,2] [,3]
## [1,]   1    2    3
## [2,]   2    3    4
## [3,]   3    4    5

By specifying ncol = 3, we mean that the provided vector should be regarded as a matrix with 3 columns (and 3 rows automatically). You may feel the original vector is not as straightforward as its representation. To make ...

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