select_helpers | R Documentation |
These functions allow you to select variables based on their names.
starts_with()
: Starts with a prefix.
ends_with()
: Ends with a prefix.
contains()
: Contains a literal string.
matches()
: Matches a regular expression.
all_of()
: Matches variable names in a character vector. All names must be present, otherwise an error is thrown.
any_of()
: The same as all_of()
except it doesn't throw an error.
everything()
: Matches all variables.
last_col()
: Select the last variable, possibly with an offset.
starts_with(match, ignore.case = TRUE, vars = peek_vars())
ends_with(match, ignore.case = TRUE, vars = peek_vars())
contains(match, ignore.case = TRUE, vars = peek_vars())
matches(match, ignore.case = TRUE, perl = FALSE, vars = peek_vars())
num_range(prefix, range, width = NULL, vars = peek_vars())
all_of(x, vars = peek_vars())
any_of(x, vars = peek_vars())
everything(vars = peek_vars())
last_col(offset = 0L, vars = peek_vars())
match |
|
ignore.case |
|
vars |
|
perl |
|
prefix |
A prefix which starts the numeric range. |
range |
|
width |
|
x |
|
offset |
|
An integer vector giving the position of the matched variables.
select()
, relocate()
, where()
, group_cols()
mtcars %>% select(starts_with("c"))
mtcars %>% select(starts_with(c("c", "h")))
mtcars %>% select(ends_with("b"))
mtcars %>% relocate(contains("a"), .before = mpg)
iris %>% select(matches(".t."))
mtcars %>% select(last_col())
# `all_of()` selects the variables in a character vector:
iris %>% select(all_of(c("Petal.Length", "Petal.Width")))
# `all_of()` is strict and will throw an error if the column name isn't found
try({iris %>% select(all_of(c("Species", "Genres")))})
# However `any_of()` allows missing variables
iris %>% select(any_of(c("Species", "Genres")))
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