How can I remove an element from a list?

by

If you don’t want to modify the list in-place (e.g. for passing the list with an element removed to a function), you can use indexing: negative indices mean “don’t include this element”.

x <- list("a", "b", "c", "d", "e"); # example list

x[-2];       # without 2nd element

x[-c(2, 3)]; # without 2nd and 3rd

Also, logical index vectors are useful:

x[x != "b"]; # without elements that are "b"

This works with dataframes, too:

df <- data.frame(number = 1:5, name = letters[1:5])

df[df$name != "b", ];     # rows without "b"

df[df$number %% 2 == 1, ] # rows with odd numbers only

More Related Contents:

  1. How do I make a list of data frames?
  2. The difference between bracket [ ] and double bracket [[ ]] for accessing the elements of a list or dataframe
  3. Simultaneously merge multiple data.frames in a list
  4. Combine a list of data frames into one data frame by row
  5. Index values from a matrix using row, col indices
  6. How to index an element of a list object in R
  7. Convert list to data frame while keeping list-element names
  8. Collapse / concatenate / aggregate a column to a single comma separated string within each group
  9. Filter data.frame rows by a logical condition
  10. Evaluate expression given as a string
  11. Pass a data.frame column name to a function
  12. What is the difference between require() and library()?
  13. How to sort a character vector where elements contain letters and numbers in R?
  14. Plot two graphs in same plot in R
  15. Add column which contains binned values of a numeric column
  16. Replace all 0 values to NA
  17. Can lists be created that name themselves based on input object names?
  18. Scheduling R Script
  19. Calculate group mean, sum, or other summary stats. and assign column to original data
  20. What are the main differences between R data files?
  21. Finding All Positions for Multiple Elements in a Vector
  22. Get filename without extension in R
  23. ending “+” prompt in R
  24. Create categorical variable in R based on range
  25. Apply several summary functions (sum, mean, etc.) on several variables by group in one call
  26. Order of operator precedence when using “:” (the colon)
  27. Creating a named list from two vectors (names, values)
  28. in r combine a list of lists into one list
  29. How to combine two lists in R
  30. R: How to split a data frame into training, validation, and test sets?

Leave a Comment