R min() and max()

In R, we can find the minimum or maximum value of a vector or data frame.

We use the min() and max() function to find minimum and maximum value respectively.

• The min() function returns the minimum value of a vector or data frame.
• The max() function returns the maximum value of a vector or data frame.

Syntax of min() and max() in R

The syntax of the min() and max() function is

For min()

min(collection, na.rm = Boolean)

For max()

max(collection, na.rm = Boolean)

In both the syntax,

• collection – is a vector or data frame
• na.rm (optional) – is a boolean value that indicates whether value should be kept or removed,

Example 1: Use of min() in R

numbers <- c(2,4,6,8,10)
 
# return minimum value present in numbers
min(numbers)  # 2

characters <- c("s", "a", "p", "b")

# return alphabetically minimum value in characters
min(characters)  # "a"

Output

[1] 2
[1] "a"

Here,

• min(numbers) – returns the smallest number in numbers i.e. 2
• min(characters) – returns alphabetically minimum value in characters i.e. "a"

Example 2: Use of max() in R

numbers <- c(2,4,6,8,10)
 
# return largest value present in numbers
max(numbers)  # 10

characters <- c("s", "a", "p", "b")

# return alphabetically maximum value in characters
max(characters)  # "s"

Output

[1] 10
[1] "s"

Here,

• max(numbers) – returns the largest number in numbers i.e. 10
• max(characters) – returns alphabetically maximum value in characters i.e. "s"

min() and max() in R with NA Values

While working on a large data set, we may encounter NA (Not Applicable) values in a vector.

In this case the min() function doesn’t give desired output if NA is present. For example,

numbers <- c(2, NA, 6, 7, NA, 10)
 
# return smallest value 
min(numbers)  # NA

Output

[1] NA

Here, we get NA as output. But that is not the desired output.

So we can handle this using na.rm argument

numbers <- c(2, NA, 6, 7, NA, 10)
 
# return smallest value 
min(numbers, na.rm = TRUE)  # 2

Output

[1] 2

Here, we have used the na.rm argument to handle NA values.

By setting na.rm to TRUE, we have removed NA before the computation. So the output will be 2 not NA.

Note: Similar to min(), we can use max() with NA values too.

min() and max() in a Data Frame

In R, we can use min() and max() to find minimum and maximum value in a certain column of a data frame. For example,

# Create a data frame
dataframe1 <- data.frame (
  Name = c("Juan", "Kay", "Jay", "Ray", "Aley"),
  Age = c(22, 15, 19, 30, 23),
  ID = c(101, 102, 103, 104, 105)
)

# return maximum value of Age column of dataframe1
print(max(dataframe1$Age)) # 30

# return minimum value of ID column of dataframe1 
print(min(dataframe1$ID)) # 101

Output

[1] 30
[1] 101

Here, we have used the max() and min() function to find the maximum and minimum value of the Age and ID column respectively.

• max(dataframe1$Age) – returns the maximum value from the Age column of dataframe1 i.e. 30.
• min(dataframe1$ID) – returns the minimum value from the ID column of dataframe1 i.e. 101.