Reverse-score variables (change the keying/scoring direction).
reverse(x, ...)reverse_scale(x, ...)
# S3 method for numeric
reverse(x, range = NULL, verbose = TRUE, ...)
# S3 method for data.frame
reverse(
x,
select = NULL,
exclude = NULL,
range = NULL,
append = FALSE,
ignore_case = FALSE,
regex = FALSE,
verbose = FALSE,
...
)
A reverse-scored object.
A (grouped) data frame, numeric vector or factor.
Arguments passed to or from other methods.
Range of values that is used as reference for reversing the
scale. For numeric variables, can be NULL
or a numeric vector of length
two, indicating the lowest and highest value of the reference range. If
NULL
, will take the range of the input vector (range(x)
). For factors,
range
can be NULL
, a numeric vector of length two, or a (numeric)
vector of at least the same length as factor levels (i.e. must be equal
to or larger than nlevels(x)
). Note that providing a range
for factors
usually only makes sense when factor levels are numeric, not characters.
Toggle warnings.
Variables that will be included when performing the required tasks. Can be either
a variable specified as a literal variable name (e.g., column_name
),
a string with the variable name (e.g., "column_name"
), or a character
vector of variable names (e.g., c("col1", "col2", "col3")
),
a formula with variable names (e.g., ~column_1 + column_2
),
a vector of positive integers, giving the positions counting from the left
(e.g. 1
or c(1, 3, 5)
),
a vector of negative integers, giving the positions counting from the
right (e.g., -1
or -1:-3
),
one of the following select-helpers: starts_with()
, ends_with()
,
contains()
, a range using :
or regex("")
. starts_with()
,
ends_with()
, and contains()
accept several patterns, e.g
starts_with("Sep", "Petal")
.
or a function testing for logical conditions, e.g. is.numeric()
(or
is.numeric
), or any user-defined function that selects the variables
for which the function returns TRUE
(like: foo <- function(x) mean(x) > 3
),
ranges specified via literal variable names, select-helpers (except
regex()
) and (user-defined) functions can be negated, i.e. return
non-matching elements, when prefixed with a -
, e.g. -ends_with("")
,
-is.numeric
or -(Sepal.Width:Petal.Length)
. Note: Negation means
that matches are excluded, and thus, the exclude
argument can be
used alternatively. For instance, select=-ends_with("Length")
(with
-
) is equivalent to exclude=ends_with("Length")
(no -
). In case
negation should not work as expected, use the exclude
argument instead.
If NULL
, selects all columns. Patterns that found no matches are silently
ignored, e.g. extract_column_names(iris, select = c("Species", "Test"))
will just return "Species"
.
See select
, however, column names matched by the pattern
from exclude
will be excluded instead of selected. If NULL
(the default),
excludes no columns.
Logical or string. If TRUE
, recoded or converted variables
get new column names and are appended (column bind) to x
, thus returning
both the original and the recoded variables. The new columns get a suffix,
based on the calling function: "_r"
for recode functions, "_n"
for
to_numeric()
, "_f"
for to_factor()
, or "_s"
for
slide()
. If append=FALSE
, original variables in x
will be
overwritten by their recoded versions. If a character value, recoded
variables are appended with new column names (using the defined suffix) to
the original data frame.
Logical, if TRUE
and when one of the select-helpers or
a regular expression is used in select
, ignores lower/upper case in the
search pattern when matching against variable names.
Logical, if TRUE
, the search pattern from select
will be
treated as regular expression. When regex = TRUE
, select must be a
character string (or a variable containing a character string) and is not
allowed to be one of the supported select-helpers or a character vector
of length > 1. regex = TRUE
is comparable to using one of the two
select-helpers, select = contains("")
or select = regex("")
, however,
since the select-helpers may not work when called from inside other
functions (see 'Details'), this argument may be used as workaround.
For most functions that have a select
argument (including this function),
the complete input data frame is returned, even when select
only selects
a range of variables. That is, the function is only applied to those variables
that have a match in select
, while all other variables remain unchanged.
In other words: for this function, select
will not omit any non-included
variables, so that the returned data frame will include all variables
from the input data frame.
Other transform utilities:
normalize()
,
ranktransform()
,
rescale()
,
standardize()
reverse(c(1, 2, 3, 4, 5))
reverse(c(-2, -1, 0, 2, 1))
# Specify the "theoretical" range of the input vector
reverse(c(1, 3, 4), range = c(0, 4))
# Factor variables
reverse(factor(c(1, 2, 3, 4, 5)))
reverse(factor(c(1, 2, 3, 4, 5)), range = 0:10)
# Data frames
head(reverse(iris))
head(reverse(iris, select = "Sepal.Length"))
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