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How to Handle “undefined columns selected” in R?

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In this article, we will discuss how to handle “undefined columns selected” error in R Programming Language.

This error is specific to dataframe in R. This type of error will occur when we select a subset of a data frame and forget to add a comma.

Example: Check the error in the dataframe

Here we created a dataframe with 3 columns and select the values in which the second column value is greater than 45

R




# create dataframe with 4 rows and 3 columns
data = data.frame(marks1=c(98, 90, 89, 78), 
                  marks2=c(100, 89, 91, 76), 
                  marks3=c(78, 89, 79, 94))
  
# display
print(data)
  
# now select values from marks2 column 
# which are greater than 45
data[data$marks1 > 45]


Output:

This is because of neglecting comma(,) behind the value. The dataframe must choose the column after comma operator. So we have to keep comma.

Example:

R




# create dataframe with 4 rows and 
# 3 columns
data = data.frame(marks1=c(98, 90, 89, 78),
                  marks2=c(100, 89, 91, 76),
                  marks3=c(78, 89, 79, 94))
  
# display
print(data)
  
# now select values from marks2 column 
# which are greater than 90
data[data$marks1 > 90, ]


Output:


Last Updated : 28 Nov, 2021
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