# Extract Matrix Values by Row & Column Names in R (3 Examples)

In this tutorial, I’ll illustrate how to get certain column and row values using column and row names of a matrix in the R programming language.

## Introducing Example Data

mat <- matrix(1:20, ncol = 4) # Constructing matrix in R rownames(mat) <- paste0("r", 1:5) # Setting up row names colnames(mat) <- paste0("c", 1:4) # Setting up column names mat # Showing example matrix in RStudio console # c1 c2 c3 c4 # r1 1 6 11 16 # r2 2 7 12 17 # r3 3 8 13 18 # r4 4 9 14 19 # r5 5 10 15 20 |

mat <- matrix(1:20, ncol = 4) # Constructing matrix in R rownames(mat) <- paste0("r", 1:5) # Setting up row names colnames(mat) <- paste0("c", 1:4) # Setting up column names mat # Showing example matrix in RStudio console # c1 c2 c3 c4 # r1 1 6 11 16 # r2 2 7 12 17 # r3 3 8 13 18 # r4 4 9 14 19 # r5 5 10 15 20

## Example 1: Using Row Names to Extract Particular Rows from Matrix

mat[c("r1", "r4"), ] # Selecting certain rows # c1 c2 c3 c4 # r1 1 6 11 16 # r4 4 9 14 19 |

mat[c("r1", "r4"), ] # Selecting certain rows # c1 c2 c3 c4 # r1 1 6 11 16 # r4 4 9 14 19

## Example 2: Using Column Names to Extract Particular Variables from Matrix

mat[ , c("c2", "c3")] # Selecting certain columns # c2 c3 # r1 6 11 # r2 7 12 # r3 8 13 # r4 9 14 # r5 10 15 |

mat[ , c("c2", "c3")] # Selecting certain columns # c2 c3 # r1 6 11 # r2 7 12 # r3 8 13 # r4 9 14 # r5 10 15

## Example 3: Using Row & Column Names to Extract Particular Rows & Columns from Matrix

mat[c("r2", "r4", "r5"), # Selecting certain rows & columns c("c3", "c4")] # c2 c3 # r1 6 11 # r2 7 12 # r3 8 13 # r4 9 14 # r5 10 15 |

mat[c("r2", "r4", "r5"), # Selecting certain rows & columns c("c3", "c4")] # c2 c3 # r1 6 11 # r2 7 12 # r3 8 13 # r4 9 14 # r5 10 15

## Further Resources & Related Articles

Here, you may find some additional resources on topics such as data inspection, indices, and extracting data.