shifts shifts rows of data down (n < 0) for lags or up (n
> 0) for leads replacing the undefined data with a user-defined value (e.g.,
NA). The number of rows shifted is equal to abs(n). It is assumed that
data[vrb.nm] is already sorted by time such that the first row is
earliest in time and the last row is the latest in time.
shifts(data, vrb.nm, n, undefined = NA, suffix)data.frame of shifted data with colnames specified by suffix.
data.frame of data.
character vector of colnames from data specifying the
variables.
integer vector of length 1. Specifies the direction and magnitude of the shift. See details.
atomic vector of length 1 (probably makes sense to be the
same typeof as the vectors in data[vrb.nm]). Specifies what to
insert for undefined values after the shifting takes place. See details.
character vector of length 1 specifying the string to append to
the end of the colnames of the return object. The default depends on the
n argument: 1) if n < 0, then suffix =
paste0("_g", -n), 2) if n > 0, then suffix =
paste0("_d", +n), 3) if n = 0, then suffix = "".
If n is negative, then shifts inserts undefined into the
first abs(n) rows of data[vrb.nm], shifting all other rows of
x down abs(n) positions, and then dropping the last
abs(n) row of data[vrb.nm] to preserve the original nrow of
data. If n is positive, then shifts drops the first
abs(n) rows of x, shifting all other rows of
data[vrb.nm] up abs(n) positions, and then inserts
undefined into the last abs(n) rows of x to preserve the
original length of data. If n is zero, then shifts simply
returns data[vrb.nm].
It is recommended to use L when specifying n to prevent
problems with floating point numbers. shifts tries to circumvent this
issue by a call to round within shifts if n is not an
integer; however that is not a complete fail safe. The problem is that
as.integer(n) implicit in shifts truncates rather than rounds.
shift
shifts_by
shift_by
shifts(data = attitude, vrb.nm = colnames(attitude), n = -1L)
shifts(data = mtcars, vrb.nm = colnames(mtcars), n = 2L)
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