What is a Matrix?

A matrix is a two-dimensional data structure in R, which means that every matrix element can be characterized by its position among rows and columns. Matrices in R can contain data of only one type, i.e., a matrix can not contain numbers and text simultaneously.

There are several ways to create a matrix in R. On one side, you can 'merge' two rows; on the other, you can 'merge' two columns. Let's consider each method separately. The first one is the rbind() function. Function name comes from Rows Bind - this function connects vectors as rows.

# Rows

row_1 = c(1, 2, 3)

row_2 = c(4, 5, 6)

# Merge two rows

rbind(row_1, row_2)


              12345
            
# Rows
row_1 = c(1, 2, 3)
row_2 = c(4, 5, 6)
# Merge two rows
rbind(row_1, row_2)

As you can see, this matrix has two rows and three columns (since each row has three values). Another way - is to use cbind() function. Likewise, the previous function, name of this function comes from Columns Bind. Let's look at the example.

# Columns

col_1 = c(1, 2, 3)

col_2 = c(4, 5, 6)

# Merge two columns

cbind(col_1, col_2)


              12345
            
# Columns
col_1 = c(1, 2, 3)
col_2 = c(4, 5, 6)
# Merge two columns
cbind(col_1, col_2)

As you can see, this matrix has two columns and three rows (since each column has three values).

Task

Swipe to start coding

Practice creating matrices by yourself using both methods!

Create two vectors: a with integers from 1 to 4, and b with integers from 5 to 8 using the colon : sign.
Create and output matrix by merging a and b as rows.
Create and output matrix by merging a and b as columns.