Sort Matrix According to First Column in R

In this article, we will discuss how to sort a matrix according to the first column in R programming language.

Matrix in use:

We can sort the matrix according to a specific column by using the order() function with indexing. To sort according to first column 1 is passed in place of column index.

Syntax:

matrix[order(matrix[ , 1]), ] 

where,

• matrix is the input matrix pass with an index
• order() function takes one parameter that is matrix with 1 st column index

Example: R program to sort a matrix according to first column

R

# create a matrix with 4 rows and 5 columns
# - 20 elements
data = matrix(c(1, 13, 4, 5, 6, 78, 56, 23, 34, 1, 23,
                45, 67, 23, 34, 78, 97, 45, 0, 9),
              nrow=4, ncol=5)

print("Actual matrix")

print(data)

print("sorted matrix")

# display sorted data according to first column
final = data[order(data[, 1]), ]

print(final)

Output:

Example: R program to sort a matrix according to first column

R

# create a matrix with 2 rows and 2 columns
# - 4 elements
data= matrix(c(11,2,23,1),nrow=2,ncol=2)

print("Actual matrix")

print(data)

print("sorted matrix")

# display sorted data according to first column
final=data[order(data[ , 1]), ]

print( final)

Output: