Description Usage Arguments Details Value See Also Examples
View source: R/quest_functions.R
shifts
shifts rows of data down (n
< 0) for lags or up (n
> 0) for leads replacing the undefined data with a userdefined 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.
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data 
data.frame of data. 
vrb.nm 
character vector of colnames from 
n 
integer vector of length 1. Specifies the direction and magnitude of the shift. See details. 
undefined 
atomic vector of length 1 (probably makes sense to be the
same typeof as the vectors in 
suffix 
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

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.
data.frame of shifted data with colnames specified by suffix
.
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