You can use the following methods to replace specific values in a matrix in R:

**Method 1: Replace Elements Equal to Specific Value**

#replace 5 with 100 my_matrix[my_matrix==5] <- 100

**Method 2: Replace Elements Based on One Condition**

#replace elements with value less than 15 with 0 my_matrix[my_matrix<15] <- 0

**Method 3: Replace Elements Based on Multiple Conditions**

#replace elements with value between 10 and 15 with 99 my_matrix[my_matrix>=10 & my_matrix<=15] <- 99

The following examples show how to use each method in practice with the following matrix in R:

#create matrix my_matrix <- matrix(1:20, nrow = 5) #display matrix my_matrix [,1] [,2] [,3] [,4] [1,] 1 6 11 16 [2,] 2 7 12 17 [3,] 3 8 13 18 [4,] 4 9 14 19 [5,] 5 10 15 20

**Example 1: Replace Elements Equal to Specific Value**

The following code shows how to replace all elements equal to the value **5** with the value **100**:

#replace 5 with 100 my_matrix[my_matrix==5] <- 100 #view updated matrix my_matrix [,1] [,2] [,3] [,4] [1,] 1 6 11 16 [2,] 2 7 12 17 [3,] 3 8 13 18 [4,] 4 9 14 19 [5,] 100 10 15 20

Notice that the one element equal to the value **5** has been replaced with a value of **100**.

All other elements remained unchanged in the matrix.

**Example 2: Replace Elements Based on One Condition**

The following code shows how to replace all elements that have a value less than **15** with the value **0**:

#replace elements with value less than 15 with 100 my_matrix[my_matrix<15] <- 0 #view updated matrix my_matrix [,1] [,2] [,3] [,4] [1,] 0 0 0 16 [2,] 0 0 0 17 [3,] 0 0 0 18 [4,] 0 0 0 19 [5,] 0 0 15 20

Notice that each of the elements that have a value less than **15** have been replaced with a value of **0**.

**Example 3: Replace Elements Based on Multiple Conditions**

The following code shows how to replace all elements that have a value between **10** and **15** with a value of **99**:

#replace elements with value between 10 and 15 with 99 my_matrix[my_matrix>=10 & my_matrix<=15] <- 99 #view updated matrix my_matrix [,1] [,2] [,3] [,4] [1,] 1 6 99 16 [2,] 2 7 99 17 [3,] 3 8 99 18 [4,] 4 9 99 19 [5,] 5 99 99 20

Notice that each of the elements that have a value between **10** and **15** have been replaced with a value of **99**.

**Additional Resources**

The following tutorials explain how to perform other common tasks in R:

How to Sort a Matrix in R

How to Remove NA from Matrix in R

How to Convert Data Frame to Matrix in R

How to Convert a Table to a Matrix in R