18 Matrices.r

# A matrix can be created with the matrix() function. Specify the nrow and ncol parameters to get the amount of rows and columns


# Create a matrix
thismatrix <- matrix(c(1,2,3,4,5,6), nrow = 3, ncol = 2)


# Printing the matrix
thismatrix


#Access Matrix Items

thismatrix <- matrix(c("apple", "banana", "cherry", "orange"), nrow = 2, ncol = 2)
thismatrix
thismatrix[1, 2]


# Accessing the Second row
thismatrix <- matrix(c("apple", "banana", "cherry", "orange"), nrow = 2, ncol = 2)

thismatrix[2,]


# More than one row can be accessed if you use the c() function:

thismatrix <- matrix(c("apple", "banana", "cherry", "orange","grape", "pineapple", "pear", "melon", "fig"), nrow = 3, ncol = 3)

thismatrix[c(1,2),]


# More than one column can be accessed if you use the c() function:
thismatrix <- matrix(c("apple", "banana", "cherry", "orange","grape", "pineapple", "pear", "melon", "fig"), nrow = 3, ncol = 3)

thismatrix[, c(1,2)]


# Use the cbind() function to add additional columns in a Matrix:
thismatrix <- matrix(c("apple", "banana", "cherry", "orange","grape", "pineapple", "pear", "melon", "fig"), nrow = 3, ncol = 3)

newmatrix <- cbind(thismatrix, c("strawberry", "blueberry", "raspberry"))

newmatrix


# Use the rbind() function to add additional rows in a Matrix:
thismatrix <- matrix(c("apple", "banana", "cherry", "orange","grape", "pineapple", "pear", "melon", "fig"), nrow = 3, ncol = 3)

newmatrix <- rbind(thismatrix, c("strawberry", "blueberry", "raspberry"))

newmatrix


#Use the c() function to remove rows and columns in a Matrix:
thismatrix <- matrix(c("apple", "banana", "cherry", "orange", "mango", "pineapple"), nrow = 3, ncol =2)

#Remove the first row and the first column
thismatrix <- thismatrix[-c(1), -c(1)]

thismatrix


#To find out if a specified item is present in a matrix, use the %in% operator:
thismatrix <- matrix(c("apple", "banana", "cherry", "orange"), nrow = 2, ncol = 2)

"apple" %in% thismatrix