Vectors vs Matrices

 Difference Between Vectors and Matrices

The main differences between vectors and matrices in r programming:

Feature	Vectors	Matrices
Dimensionality	1D	2D
Syntax	c(1, 2, 3)	matrix(1:9, nrow=3)
Element Access	vec[1]	mat[1, 2]
Element Addition	vec <- c(vec, 4)	mat <- rbind(mat, c(10, 11, 12)) <br> mat <- cbind(mat, c(4, 5, 6))
Element Deletion	vec <- vec[-2]	mat <- mat[-2, ] <br> mat <- mat[, -2]
Concatenation	c(vec1, vec2)	rbind(mat1, mat2) <br> cbind(mat1, mat2)
Mathematical Ops	vec1 + vec2	mat1 + mat2
Element-wise Ops	vec1 * vec2	mat1 * mat2
Transpose	t(vec)	t(mat)
Special Functions	sum(vec)	apply(mat, 1, sum)
Names	vec <- c(a=1, b=2, c=3)	colnames(mat) <- c("A", "B", "C") <br> rownames(mat) <- c("X", "Y", "Z")

Ø    Some additional points of difference are:

i.             Vectors can have any length, whereas matrices have to have a specified number of rows and columns.

ii.            Vectors are 1-dimensional, whereas matrices are 2-dimensional. This means that vectors have only one "axis" or "dimension" to them, whereas matrices have two (rows and columns).

iii.           Vectors are usually created using the c() function, whereas matrices are created using the matrix() function (although matrices can also be created using other functions like cbind() and rbind()).

iv.           Accessing an element of a vector requires only one index (e.g. vec[1]), whereas accessing an element of a matrix requires two indices, one for the row and one for the column (e.g. mat[1, 2]).

v.            Vectors can be concatenated using the c() function, whereas matrices can be concatenated using either rbind() (for concatenating rows) or cbind() (for concatenating columns).

vi.           Mathematical operations on vectors (e.g. vec1 + vec2) are performed element-wise, whereas mathematical operations on matrices (e.g. mat1 + mat2) are performed element-wise on the corresponding elements.

vii.         Special functions like sum() can be applied to vectors to compute a summary statistic, whereas for matrices, the apply() function is typically used to apply a function to either rows or columns (specified by the second argument).

viii.        Vectors can have named elements, whereas matrices can have named rows and columns (specified using the rownames() and colnames() functions).