Practice: Arrays and Matrices

Challenge 1

Write a R program to create a matrix taking a given vector of numbers as input and define the column and row names. Display the matrix.

Sample Output 1

[1] "Original Matrix:"
     col1 col2 col3 col4
row1    1    2    3    4
row2    5    6    7    8
row3    9   10   11   12
row4   13   14   15   16

Challenge 2

Write an R program to convert a matrix to a 1-dimensional array.

Sample Output 2

[1] "Original Matrix:"
col1 col2 col3 col4
row1 1 2 3 4 
row2 5 6 7 8
row3 9 10 11 12
row4 13 14 15 16
[1] "1 dimensional array (column wise):" 
[1] 1 5 9 13 2 6 10 14 3 7 11 15 4 8 12 16
[1] "1 dimensional array (row wise):"
[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Challenge 3

Write a R program to access the element at 3rd column and 2nd row, only the 3rd row and only the 4th column of a given matrix.

Sample Output 3

[1] "Original Matrix:"
     col1 col2 col3 col4
row1    1    2    3    4
row2    5    6    7    8
row3    9   10   11   12
row4   13   14   15   16
[1] "Access the element at 3rd column and 2nd row:"
[1] 7
[1] "Access only the  3rd row:"
col1 col2 col3 col4 
   9   10   11   12 
[1] "Access only the 4th column:"
row1 row2 row3 row4 
   4    8   12   16     

Source: w3resource, https://www.w3resource.com/r-programming-exercises/matrix/index.php
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