You can use the following methods to calculate the median value of rows in R:
Method 1: Calculate Median of Rows Using Base R
df$row_median = apply(df, 1, median, na.rm=TRUE)
Method 2: Calculate Median of Rows Using dplyr
library(dplyr) df %>% rowwise() %>% mutate(row_median = median(c_across(where(is.numeric)), na.rm=TRUE))
The following examples show how to use each method in practice.
Example 1: Calculate Median of Rows Using Base R
Suppose we have the following data frame in R that shows the points scored by various basketball players during three different games:
#create data frame
df <- data.frame(game1=c(10, 12, 14, 15, 16, 18, 19),
game2=c(14, 19, 13, 8, 15, 15, 17),
game3=c(9, NA, 15, 25, 26, 30, 19))
#view data frame
df
game1 game2 game3
1 10 14 9
2 12 19 NA
3 14 13 15
4 15 8 25
5 16 15 26
6 18 15 30
7 19 17 19
We can use the apply() function from base R to create a new column that shows the median value of each row:
#calculate median of each row
df$row_median = apply(df, 1, median, na.rm=TRUE)
#view updated data frame
df
game1 game2 game3 row_median
1 10 14 9 10.0
2 12 19 NA 15.5
3 14 13 15 14.0
4 15 8 25 15.0
5 16 15 26 16.0
6 18 15 30 18.0
7 19 17 19 19.0
The new column called row_median contains the median value of each row in the data frame.
Example 2: Calculate Median of Rows Using dplyr
Suppose we have the following data frame in R that shows the points scored by various basketball players during three different games:
#create data frame
df <- data.frame(player=c('A', 'B', 'C', 'D', 'E', 'F', 'G'),
game1=c(10, 12, 14, 15, 16, 18, 19),
game2=c(14, 19, 13, 8, 15, 15, 17),
game3=c(9, NA, 15, 25, 26, 30, 19))
#view data frame
df
player game1 game2 game3
1 A 10 14 9
2 B 12 19 NA
3 C 14 13 15
4 D 15 8 25
5 E 16 15 26
6 F 18 15 30
7 G 19 17 19
We can use the mutate() function from the dplyr package to create a new column that shows the median value of each row for the numeric columns only:
library(dplyr)
#calculate median of rows for numeric columns only
df %>%
rowwise() %>%
mutate(row_median = median(c_across(where(is.numeric)), na.rm=TRUE))
# A tibble: 7 x 5
# Rowwise:
player game1 game2 game3 row_median
1 A 10 14 9 10
2 B 12 19 NA 15.5
3 C 14 13 15 14
4 D 15 8 25 15
5 E 16 15 26 16
6 F 18 15 30 18
7 G 19 17 19 19
The new column called row_median contains the median value of each row in the data frame for the numeric columns only.
Additional Resources
The following tutorials explain how to perform other common tasks in R:
How to Replace NA with Median in R
How to Calculate a Trimmed Mean in R
How to Calculate a Weighted Mean in R