How do you remove columns from a data.frame?

by

I use data.table‘s := operator to delete columns instantly regardless of the size of the table.

DT[, coltodelete := NULL]

or

DT[, c("col1","col20") := NULL]

or

DT[, (125:135) := NULL]

or

DT[, (variableHoldingNamesOrNumbers) := NULL]

Any solution using <- or subset will copy the whole table. data.table‘s := operator merely modifies the internal vector of pointers to the columns, in place. That operation is therefore (almost) instant.

More Related Contents:

  1. Dynamically select data frame columns using $ and a character value
  2. Simultaneously merge multiple data.frames in a list
  3. Drop unused factor levels in a subsetted data frame
  4. Merging a lot of data.frames [duplicate]
  5. dplyr: nonstandard column names (white space, punctuation, starts with numbers)
  6. Remove columns with zero values from a dataframe
  7. Calculating statistics on subsets of data [duplicate]
  8. How to convert dataframe into time series?
  9. Identifying duplicate columns in a dataframe
  10. Merge unequal dataframes and replace missing rows with 0
  11. R pass variable column indices to ggplot2 [duplicate]
  12. How to access the last value in a vector?
  13. What can R do about a messy data format?
  14. Removing display of row names from data frame
  15. Why is plyr so slow?
  16. What is the right way to multiply data frame by vector?
  17. How to delete rows from a data.frame, based on an external list, using R?
  18. Add extra level to factors in dataframe
  19. Determine the data types of a data frame’s columns
  20. finding close match from data frame 1 in data fame 2
  21. Combine several data frames in the global environment by row (rbind)
  22. Changing Million/Billion abbreviations into actual numbers? ie. 5.12M -> 5,120,000 [duplicate]
  23. Extract text after “/” in a data frame column
  24. What is difference between dataframe and list in R?
  25. Define dimensions of an empty dataframe
  26. use multiple columns as variables with sapply
  27. Merge overlapping ranges into unique groups, in dataframe
  28. Deleting specific rows from a data frame
  29. Count number of non-NA values for every column in a dataframe [duplicate]
  30. Color one point and add an annotation in ggplot2?

Leave a Comment