R dplyr: Drop multiple columns

user_3873105 0
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I have a dataframe and list of columns in that dataframe that I'd like to drop. Let's use the iris dataset as an example. I'd like to drop Sepal.Length and Sepal.Width and use only the remaining columns. How do I do this using select or select_ from the dplyr package?

Here's what I've tried so far:

drop.cols <- c('Sepal.Length', 'Sepal.Width')
iris %>% select(-drop.cols)

Error in -drop.cols : invalid argument to unary operator

iris %>% select_(.dots = -drop.cols)

Error in -drop.cols : invalid argument to unary operator

iris %>% select(!drop.cols)

Error in !drop.cols : invalid argument type

iris %>% select_(.dots = !drop.cols)

Error in !drop.cols : invalid argument type

I feel like I'm missing something obvious because these seems like a pretty useful operation that should already exist. On Github, someone posted a similar issue, and Hadley said to use 'negative indexing'. That's what (I think) I've tried, but to no avail. Any suggestions?

dplyr r
10 Answers

For anyone arriving here wanting to drop a range of columns.

Minimal reproducible example

Drop a range of columns like so:

iris %>% 
  select(-(Sepal.Width:Petal.Width)) %>% 
  head

#   Sepal.Length Species
# 1          5.1  setosa
# 2          4.9  setosa
# 3          4.7  setosa
# 4          4.6  setosa
# 5          5.0  setosa
# 6          5.4  setosa

Note:

  • The (, ) around the column names is important and must be used
user_57837450

If you have a special character in the column names, either select or select_may not work as expected. This property of dplyr of using ".". To refer to the data set in the question, the following line can be used to solve this problem:

drop.cols <- c('Sepal.Length', 'Sepal.Width')
  iris %>% .[,setdiff(names(.),drop.cols)]
user_98279040

Another way is to mutate the undesired columns to NULL, this avoids the embedded parentheses :

head(iris,2) %>% mutate_at(drop.cols, ~NULL)
#   Petal.Length Petal.Width Species
# 1          1.4         0.2  setosa
# 2          1.4         0.2  setosa
user_22704750

You can try 

iris %>% select(-!!drop.cols)
user_70665070

I also faced the same issue, but the main error was in including library which has another function definition with the same name as "select()". For me it was clashing with the MASS package select function.

After detaching the MASS library, the error stopped.

user_159014920
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