Vector-class-leftovers: Vector objects (old man page)
Description
IMPORTANT NOTE - 4/29/2014: This man page is being refactored. Most of
the things that used to be documented here have been moved to the man
page for Vector objects located in the S4Vectors
package.
Evaluation
In the following code snippets, x is a Vector object.
-
with(x, expr): Evaluates expr within
as.env(x) via eval(x).
-
eval(expr, envir, enclos=parent.frame()): Evaluates
expr within envir, where envir is coerced to
an environment with as.env(envir, enclos). The expr
is first processed with bquote, such that any
escaped symbols are directly resolved in the calling frame.
Convenience wrappers for common subsetting operations
In the code snippets below, x is a Vector object or regular R vector
object. The R vector object methods for window are defined in this
package and the remaining methods are defined in base R.
-
window(x, start=NA, end=NA, width=NA, frequency=NULL, delta=NULL, ...):
Extract the subsequence window from the Vector object using:
start, end, width- The start, end, or width
of the window. Two of the three are required.
frequency, delta- Optional arguments that specify
the sampling frequency and increment within the window.
In general, this is more efficient than using "[" operator.
-
window(x, start=NA, end=NA, width=NA) <- value:
Replace the subsequence window specified on the left (i.e. the
subsequence in x specified by start, end and
width) by value.
value must either be of class class(x), belong to a
subclass of class(x), or be coercible to class(x) or a
subclass of class(x).
The elements of value are repeated to create a Vector with the
same number of elements as the width of the subsequence window it is
replacing.
-
head(x, n = 6L):
If n is non-negative, returns the first n elements of the Vector
object.
If n is negative, returns all but the last abs(n) elements
of the Vector object.
-
tail(x, n = 6L):
If n is non-negative, returns the last n elements of the Vector
object.
If n is negative, returns all but the first abs(n) elements
of the Vector object.
-
rev(x):
Return a new Vector object made of the original elements in the reverse
order.
-
rep(x, times, length.out, each), rep.int(x, times):
Repeats the values in x through one of the following conventions:
times- Vector giving the number of times to repeat each
element if of length
length(x), or to repeat the whole vector
if of length 1. length.out- Non-negative integer. The desired length of
the output vector.
each- Non-negative integer. Each element of
x is
repeated each times.
-
subset(x, subset):
Return a new Vector object made of the subset using logical vector
subset, where missing values are taken as FALSE.
Combining
In the code snippets below, x is a Vector object.
mstack(..., .index.var = "name"): A variant of
stack, where the list is taken as the list of
arguments in ..., each of which should be a Vector
or vector (mixing the two will not work).
Looping
In the code snippets below, x is a Vector object.
-
tapply(X, INDEX, FUN = NULL, ..., simplify = TRUE):
Like the standard tapply function defined in the
base package, the tapply method for Vector objects applies a
function to each cell of a ragged array, that is to each (non-empty)
group of values given by a unique combination of the levels of certain
factors.
-
shiftApply(SHIFT, X, Y, FUN, ..., OFFSET = 0L, simplify = TRUE, verbose = FALSE):
Let i be the indices in SHIFT,
X_i = window(X, 1 + OFFSET, length(X) - SHIFT[i]), and
Y_i = window(Y, 1 + SHIFT[i], length(Y) - OFFSET). Calculates
the set of FUN(X_i, Y_i, ...) values and return the results in a
convenient form:
SHIFT- A non-negative integer vector of shift values.
X, Y- The Vector or R vector objects to shift.
FUN- The function, found via
match.fun, to be
applied to each set of shifted vectors. - ...
- Further arguments for
FUN. - OFFSET
- A non-negative integer offset to maintain throughout
the shift operations.
simplify- A logical value specifying whether or not the
result should be simplified to a vector or matrix if possible.
verbose- A logical value specifying whether or not to
print the
i indices to track the iterations.
-
aggregate(x, by, FUN, start = NULL, end = NULL, width = NULL,
frequency = NULL, delta = NULL, ..., simplify = TRUE)):
Generates summaries on the specified windows and returns the result in a
convenient form:
by- An object with
start, end, and
width methods. FUN- The function, found via
match.fun, to be
applied to each window of x. start, end, width- the start, end, or width
of the window. If
by is missing, then must supply two of the
three. frequency, delta- Optional arguments that specify
the sampling frequency and increment within the window.
- ...
- Further arguments for
FUN. simplify- A logical value specifying whether or not the
result should be simplified to a vector or matrix if possible.
Coercion
-
as.list(x): coerce a Vector to a list, where the ith
element of the result corresponds to x[i].
See Also
The Vector class defined and documented in the
S4Vectors package.