How to Access Factor Levels in R

How to Access Factor Levels in R ?

Answer

To access factor levels in R, you can use the levels() function. This function returns a vector of the levels of a factor. Accessing factor levels is useful when you need to inspect, modify, or use the levels in further analysis.


✐ Examples

1 Accessing Levels of a Character Factor

In this example,

  1. We start by creating a character vector named fruits which contains the values 'apple', 'banana', 'cherry', and 'apple'. This vector represents categorical data.
  2. Next, we use the factor() function to convert the fruits vector into a factor. We assign the result to a variable named fruits_factor. The factor() function automatically identifies the unique levels of the vector.
  3. We then use the levels() function to access the levels of the fruits_factor. The levels() function returns a vector of the unique levels in the factor.
  4. We print the levels of the fruits_factor to the console to see the distinct categories within the factor. This allows us to inspect the factor levels for further analysis.

R Program

fruits <- c('apple', 'banana', 'cherry', 'apple')
fruits_factor <- factor(fruits)
levels_fruits <- levels(fruits_factor)
print(levels_fruits)

Output

[1] "apple"  "banana" "cherry"

2 Accessing Levels of a Numeric Factor

In this example,

  1. We start by creating a numeric vector named grades which contains the values 85, 90, 75, and 85. This vector represents categorical data in numerical form.
  2. Next, we use the factor() function to convert the grades vector into a factor. We assign the result to a variable named grades_factor. The factor() function automatically identifies the unique levels of the vector.
  3. We then use the levels() function to access the levels of the grades_factor. The levels() function returns a vector of the unique levels in the factor.
  4. We print the levels of the grades_factor to the console to see the distinct categories within the factor. This allows us to inspect the factor levels for further analysis.

R Program

grades <- c(85, 90, 75, 85)
grades_factor <- factor(grades)
levels_grades <- levels(grades_factor)
print(levels_grades)

Output

[1] "75" "85" "90"

3 Accessing Levels of a Logical Factor

In this example,

  1. We start by creating a logical vector named responses which contains the values TRUE, FALSE, TRUE, and TRUE. This vector represents categorical data in logical form.
  2. Next, we use the factor() function to convert the responses vector into a factor. We assign the result to a variable named responses_factor. The factor() function automatically identifies the unique levels of the vector.
  3. We then use the levels() function to access the levels of the responses_factor. The levels() function returns a vector of the unique levels in the factor.
  4. We print the levels of the responses_factor to the console to see the distinct categories within the factor. This allows us to inspect the factor levels for further analysis.

R Program

responses <- c(TRUE, FALSE, TRUE, TRUE)
responses_factor <- factor(responses)
levels_responses <- levels(responses_factor)
print(levels_responses)

Output

[1] "FALSE" "TRUE"

Summary

In this tutorial, we learned How to Access Factor Levels in R language with well detailed examples.


More R Factors Tutorials

  1. How to Create Factors in R ?
  2. How to find Length of a Factor in R ?
  3. How to Loop over a Factor in R ?
  4. How to Convert Data to Factors in R ?
  5. How to Order Factor Levels in R ?
  6. How to Access Factor Levels in R ?
  7. How to Modify Factor Levels in R ?
  8. How to Reorder Factor Levels in R ?
  9. How to Add Levels to a Factor in R ?
  10. How to Drop Levels from a Factor in R ?
  11. How to Rename Levels of a Factor in R ?
  12. How to Use Factors in Data Frames in R ?
  13. How to Generate Summary Statistics for Factors in R ?
  14. How to Merge Factors in R ?
  15. How to Split Data by Factors in R ?
  16. How to Plot Factors in R ?
  17. How to Convert Factors to Numeric in R ?
  18. How to Convert Factors to Character in R ?
  19. How to Handle Missing Values in Factors in R ?
  20. How to Use Factors in Conditional Statements in R ?
  21. How to Compare Factors in R ?
  22. How to Create Ordered Factors in R ?
  23. How to Check if a Variable is a Factor in R ?
  24. How to Use Factors in Statistical Models in R ?
  25. How to Collapse Factor Levels in R ?
  26. How to Use Factors in Grouping Operations in R ?
  27. How to Use Factors in Aggregation Functions in R ?
  28. How to Deal with Unused Factor Levels in R ?
  29. How to Encode and Decode Factors in R ?
  30. How to Use Factors in Regression Analysis in R ?
  31. How to Convert Factors to Dates in R ?