tidyr used to offer twin versions of each verb suffixed with an underscore. These versions had standard evaluation (SE) semantics: rather than taking arguments by code, like NSE verbs, they took arguments by value. Their purpose was to make it possible to program with tidyr. However, tidyr now uses tidy evaluation semantics. NSE verbs still capture their arguments, but you can now unquote parts of these arguments. This offers full programmability with NSE verbs. Thus, the underscored versions are now superfluous.
Unquoting triggers immediate evaluation of its operand and inlines
the result within the captured expression. This result can be a
value or an expression to be evaluated later with the rest of the
argument. See vignette("programming", "dplyr")
for more information.
complete_(data, cols, fill = list(), ...) drop_na_(data, vars) expand_(data, dots, ...) crossing_(x) nesting_(x) extract_(data, col, into, regex = "([[:alnum:]]+)", remove = TRUE, convert = FALSE, ...) fill_(data, fill_cols, .direction = c("down", "up")) gather_(data, key_col, value_col, gather_cols, na.rm = FALSE, convert = FALSE, factor_key = FALSE) nest_(...) separate_rows_(data, cols, sep = "[^[:alnum:].]+", convert = FALSE) separate_(data, col, into, sep = "[^[:alnum:]]+", remove = TRUE, convert = FALSE, extra = "warn", fill = "warn", ...) spread_(data, key_col, value_col, fill = NA, convert = FALSE, drop = TRUE, sep = NULL) unite_(data, col, from, sep = "_", remove = TRUE) unnest_(...)
data | A data frame |
---|---|
fill | A named list that for each variable supplies a single value to
use instead of |
... | Specification of columns to expand. Columns can be atomic vectors or lists. To find all unique combinations of x, y and z, including those not
found in the data, supply each variable as a separate argument.
To find only the combinations that occur in the data, use nest:
You can combine the two forms. For example,
For factors, the full set of levels (not just those that appear in the
data) are used. For continuous variables, you may need to fill in values
that don't appear in the data: to do so use expressions like
Length-zero (empty) elements are automatically dropped. |
vars, cols, col | Name of columns. |
x | For |
into | Names of new variables to create as character vector.
Use |
regex | a regular expression used to extract the desired values.
There should be one group (defined by |
remove | If |
convert | If NB: this will cause string |
fill_cols | Character vector of column names. |
.direction | Direction in which to fill missing values. Currently either "down" (the default), "up", "downup" (i.e. first down and then up) or "updown" (first up and then down). |
key_col, value_col | Strings giving names of key and value columns to create. |
gather_cols | Character vector giving column names to be gathered into pair of key-value columns. |
na.rm | If |
factor_key | If |
sep | Separator delimiting collapsed values. |
extra | If
|
drop | If |
from | Names of existing columns as character vector |
expand_cols | Character vector of column names to be expanded. |
key_col, value_col | Strings giving names of key and value cols. |