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To find the maximum value across multiple columns in R, you can use the “max” function which takes in multiple columns as input and returns the highest value among them. This function can be applied to a specific row or across the entire dataset, depending on the desired result. Additionally, you can use the “apply” function to iterate through each column and find the maximum value. Another option is to use the “dplyr” package, which offers the “rowwise” function to find the maximum value across multiple columns for each row in a dataset. With these methods, you can easily identify the highest value among multiple columns in your data analysis process.
Find the Max Value Across Multiple Columns in R
We can use the pmax() function to find the max value across multiple columns in R. This function uses the following syntax:
pmax(…, na.rm = FALSE)
where:
- … : A list of vectors
- na.rm: A logical indicating whether missing values should be removed. Default is FALSE.
This tutorial provides several examples of how to use this function in practice using the following data frame:
#create data frame df <- data.frame(player=c('A', 'B', 'C', 'D', 'E', 'F', 'G'), points=c(28, 17, 19, 14, 23, 26, 5), rebounds=c(5, 6, 4, 7, 14, 12, 9), assists=c(10, 13, 7, 8, 4, 5, 8)) #view DataFrame df player points rebounds assists 1 A 28 5 10 2 B 17 6 13 3 C 19 4 7 4 D 14 7 8 5 E 23 14 4 6 F 26 12 5 7 G 5 9 8
Example 1: Find the Max Across Specific Columns
The following code shows how to find the max value across the points and rebounds columns in a data frame:
#find max values in each row across points and rebounds columnspmax(df$points, df$rebounds) [1] 28 17 19 14 23 26 9
Example 2: Add A New Column Containing the Max Value
The following code shows how to add a new column to the data frame that contains the max value across the points and rebounds columns:
#add new column that contains max values across points and rebounds columnsdf$max_points_rebs <- pmax(df$points, df$rebounds) #view data frame df player points rebounds assists max_points_rebs 1 A 28 5 10 28 2 B 17 6 13 17 3 C 19 4 7 19 4 D 14 7 8 14 5 E 23 14 4 23 6 F 26 12 5 26 7 G 5 9 8 9
Example 3: Add Several New Columns Containing Max Values
The following code shows how to add several new columns to the data frame that contain the max values across different groups of columns:
#add new column that contains max values across points and rebounds columnsdf$max_p_r <- pmax(df$points, df$rebounds) #add new column that contains max values across rebounds and assists columns df$max_r_a <- pmax(df$rebounds, df$assists) #view data frame df player points rebounds assists max_p_r max_r_a 1 A 28 5 10 28 10 2 B 17 6 13 17 13 3 C 19 4 7 19 7 4 D 14 7 8 14 8 5 E 23 14 4 23 14 6 F 26 12 5 26 12 7 G 5 9 8 9 9