R Programming: Convert a Matrix to a List of Column-Vectors

Last update on December 21 2024 10:11:34 (UTC/GMT +8 hours)

Write a R program to convert a given matrix to a list of column-vectors.

Sample Solution:

R Programming Code:

# Create a 4x3 matrix with values from 1 to 12
x = matrix(1:12, ncol=3)

# Print the original matrix
print("Original matrix:")
print(x)

# Print a message indicating the following output is a list of column-vectors
print("list from the said matrix:")

# Convert the matrix to a list of column-vectors
l = split(x, rep(1:ncol(x), each = nrow(x)))

# Print the resulting list of column-vectors
print(l)

Output:

[1] "Original matrix:"
     [,1] [,2] [,3]
[1,]    1    5    9
[2,]    2    6   10
[3,]    3    7   11
[4,]    4    8   12
[1] "list from the said matrix:"
$`1`
[1] 1 2 3 4

$`2`
[1] 5 6 7 8

$`3`
[1]  9 10 11 12               

Explanation:

• Create Matrix:
  • x = matrix(1:12, ncol=3):
  • Creates a matrix x with 12 elements, arranged into 3 columns. The elements are filled column-wise by default.
• Print Original Matrix:
• print("Original matrix:"):
• Prints the message "Original matrix:".
• print(x):
• Displays the content of the matrix x.
• Print Message for List Conversion:
• print("list from the said matrix:"):
• Prints the message "list from the said matrix:".
• Convert Matrix to List of Column Vectors:
• l = split(x, rep(1:ncol(x), each = nrow(x))):
• Uses the split function to convert the matrix x into a list of column-vectors.
• rep(1:ncol(x), each = nrow(x)) creates a vector that specifies how to split the matrix by columns, where 1:ncol(x) generates column indices, and each = nrow(x) repeats each index for the number of rows.
• Print Resulting List:
• print(l):
• Displays the resulting list of column-vectors.

R Programming Code Editor:

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