Operations with Matrices
Matrices in R support arithmetic operations, both with single numbers and with built-in functions that summarize their values.
Scalar Operations
Applying an arithmetic operation with a single number affects every element in the matrix.
Example
1234m <- matrix(1:9, nrow = 3, byrow = TRUE) # Multiply every element by 3 m * 3
Aggregate Functions
Functions like sum()
and mean()
compute totals or averages across the entire matrix.
Example
123456m <- matrix(1:9, nrow = 3, byrow = TRUE) # Overall mean of all elements mean(m) # Overall sum of all elements sum(m)
Row and Column Functions
You can also apply these functions to rows or columns separately with rowSums()
, rowMeans()
, colSums()
, and colMeans()
.
Example
123456m <- matrix(1:9, nrow = 3, byrow = TRUE) # Column sums colSums(m) # Row means rowMeans(m)
These functions make it easy to analyze matrix data by dimension.
Swipe to start coding
You have a matrix named m
:
2 4 6 8
10 12 14 16
Your tasks are:
- Divide each element by
2
, then add1
. Reassign the result to them
variable. - Output the matrix
m
. - Output the column totals of the
m
matrix. - Output the mean value of all
m
elements.
Solution
Thanks for your feedback!
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Operations with Matrices
Swipe to show menu
Matrices in R support arithmetic operations, both with single numbers and with built-in functions that summarize their values.
Scalar Operations
Applying an arithmetic operation with a single number affects every element in the matrix.
Example
1234m <- matrix(1:9, nrow = 3, byrow = TRUE) # Multiply every element by 3 m * 3
Aggregate Functions
Functions like sum()
and mean()
compute totals or averages across the entire matrix.
Example
123456m <- matrix(1:9, nrow = 3, byrow = TRUE) # Overall mean of all elements mean(m) # Overall sum of all elements sum(m)
Row and Column Functions
You can also apply these functions to rows or columns separately with rowSums()
, rowMeans()
, colSums()
, and colMeans()
.
Example
123456m <- matrix(1:9, nrow = 3, byrow = TRUE) # Column sums colSums(m) # Row means rowMeans(m)
These functions make it easy to analyze matrix data by dimension.
Swipe to start coding
You have a matrix named m
:
2 4 6 8
10 12 14 16
Your tasks are:
- Divide each element by
2
, then add1
. Reassign the result to them
variable. - Output the matrix
m
. - Output the column totals of the
m
matrix. - Output the mean value of all
m
elements.
Solution
Thanks for your feedback!
single