select {dplyr} | R Documentation |
select()
keeps only the variables you mention; rename()
keeps all variables.
select(.data, ...) select_(.data, ..., .dots) rename(.data, ...) rename_(.data, ..., .dots)
.data |
A tbl. All main verbs are S3 generics and provide methods
for |
... |
Comma separated list of unquoted expressions. You can treat variable names like they are positions. Use positive values to select variables; use negative values to drop variables. |
.dots |
Use |
An object of the same class as .data
.
Data frame row names are silently dropped. To preserve, convert to an explicit variable.
As well as using existing functions like :
and c
, there are
a number of special functions that only work inside select
To drop variables, use -
. You can rename variables with
named arguments.
Other single.table.verbs: arrange
,
filter
, mutate
,
slice
, summarise
iris <- tbl_df(iris) # so it prints a little nicer select(iris, starts_with("Petal")) select(iris, ends_with("Width")) select(iris, contains("etal")) select(iris, matches(".t.")) select(iris, Petal.Length, Petal.Width) vars <- c("Petal.Length", "Petal.Width") select(iris, one_of(vars)) df <- as.data.frame(matrix(runif(100), nrow = 10)) df <- tbl_df(df[c(3, 4, 7, 1, 9, 8, 5, 2, 6, 10)]) select(df, V4:V6) select(df, num_range("V", 4:6)) # Drop variables select(iris, -starts_with("Petal")) select(iris, -ends_with("Width")) select(iris, -contains("etal")) select(iris, -matches(".t.")) select(iris, -Petal.Length, -Petal.Width) # Rename variables: # * select() keeps only the variables you specify select(iris, petal_length = Petal.Length) # Renaming multiple variables uses a prefix: select(iris, petal = starts_with("Petal")) # Reorder variables: keep the variable "Species" in the front select(iris, Species, everything()) # * rename() keeps all variables rename(iris, petal_length = Petal.Length) # Programming with select --------------------------------------------------- select_(iris, ~Petal.Length) select_(iris, "Petal.Length") select_(iris, lazyeval::interp(~matches(x), x = ".t.")) select_(iris, quote(-Petal.Length), quote(-Petal.Width)) select_(iris, .dots = list(quote(-Petal.Length), quote(-Petal.Width)))