Find the index of the maximum value in R DataFrame
Last Updated :
11 Nov, 2022
In this article, we will see how to find the index of the maximum value from a DataFrame in the R Programming Language
We can find the maximum value index in a dataframe using the which.max() function.
Syntax:
which.max(dataframe_name$columnname)
"$" is used to access particular column of a dataframe.
Given below are various implementations, depicting various datatypes and situations to help you understand better.
Example 1:
R
# vector 1
data1=c("sravan","bobby","pinkey","rohith","gnanesh")
# vector 2
data2=c(98,78,79,97,89)
# creating a dataframe with names and marks
# using above vectors
final <- data.frame(names=data1,marks=data2)
print(final)
# display the maximum value index in 2 nd column
# (marks column) in a dataframe
print(paste("highest index is : ",which.max(final$marks)))
Output:
If there is more than one maximum value, then it will return index of first number which is repeated.
Example 2:
R
# vector 1
data1=c("sravan","bobby","pinkey","rohith",
"gnanesh",'divya',"satwik","chandu")
# vector 2
data2=c(98,78,79,97,89,89,99,99)
# creating a dataframe with names and marks
# using above vectors
final <- data.frame(names=data1,marks=data2)
print(final)
print(paste("highest index is : ",which.max(final$marks)))
Output:
If the data is of type character, it will find the maximum value using ASCII values.
Example 3:
R
# vector 1
data1=c("sravan","bobby","pinkey","rohith",
"gnanesh",'divya',"satwik","zhandu")
# vector 2
data2=c(98,78,79,97,89,89,99,99)
# creating a dataframe with names and marks
# using above vectors
final <- data.frame(names=data1,marks=data2)
print(final)
# display maximum value index for character values
print(paste("highest index is : ",which.max(final$names)))
Output:
Example 4:
R
# vector 1 that contains NA values as characters
data1=c(NA,"sravan",NA,NA,NA)
# vector 2 contains all data
data2=c(102,98,98,102,102)
# creating a dataframe with names and marks
# using above vectors
final <- data.frame(names=data1,marks=data2)
print(final)
# display maximum value index for character values
print(paste("highest index is : ",which.max(final$names)))
# display maximum value index for marks values
print(paste("highest index is : ",which.max(final$marks)))
Output:
If row containing all the values are same so all are higher. So it will return index of first element.
Example 5:
R
# vector contains all same data
data2=c(102,102,102,102,102)
# creating a dataframe marks using above vector
final <- data.frame(marks=data2)
print(final)
# display maximum value index for marks values
print(paste("highest index is : ",which.max(final$marks)))
Output:
If the data contains values as NA, then it will return empty.
Example 6:
R
# vector contains all NA's
data2=c(NA,NA)
# creating a dataframe marks using
# above vector
final <- data.frame(marks=data2)
print(final)
# display maximum value index for marks values
print(paste("highest index is : ",which.max(final$marks)))
Output:
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