Compute Elements of a Spike Histogram
spikecomp(
x,
method = c("tryactual", "simple", "grid"),
lumptails = 0.01,
normalize = TRUE,
y,
trans = NULL,
tresult = c("list", "segments", "roundeddata")
)
when y
is specified, a list with elements x
and y
. When method='tryactual'
the returned value depends on tresult
. For method='grid'
, a list with elements x
and y
and scalar element roundedTo
containing the typical bin width. Here x
is a character string.
a numeric variable
specifies the binning and output method. The default is 'tryactual'
and is intended to be used for spike histograms plotted in a way that allows for random x-coordinates and data gaps. No binning is done if there are less than 100 distinct values and the closest distinct x
values are distinguishable (not with 1/500th of the data range of each other). Binning uses pretty
. When trans
is specified to transform x
to reduce long tails due to outliers, pretty
rounding is not done, and lumptails
is ignored. method='grid'
is intended for sparkline spike histograms drawn with bar charts, where plotting is done in a way that x-coordinates must be equally spaced. For this method, extensive binning information is returned. For either 'tryactual'
or 'grid'
, the default if trans
is omitted is to put all values beyond the 0.01 or 0.99 quantiles into a single bin so that outliers will not create long nearly empty tails. When y
is specified, method
is ignored.
the quantile to use for lumping values into a single left and a single right bin for two of the methods
set to FALSE
to not divide frequencies by maximum frequency
a vector of frequencies corresponding to x
if you want the (x
, y
) pairs to be taken as a possibly irregular-spaced frequency tabulation for which you want to convert to a regularly-spaced tabulation like count='tabulate'
produces. If there is a constant gap between x
values, the original pairs are return, with possible removal of NA
s.
a list with three elements: the name of a transformation to make on x
, the transformation function, and the inverse transformation function. The latter is used for method='grid'
. When trans
is given lumptails
is ignored. trans
applies only to method='tryactual'
.
applies only to method='tryactual'
. The default 'list'
returns a list with elements x
, y
, and roundedTo
. method='segments'
returns a list suitable for drawing line segments, with elements x, y1, y2
. method='roundeddata'
returns a list with elements x
(non-tabulated rounded data vector after excluding NA
s) and vector roundedTo
.
Frank Harrell
Derives the line segment coordinates need to draw a spike histogram. This is useful for adding elements to ggplot2
plots. Date/time variables are handled by doing calculations on the underlying numeric scale then converting back to the original class. For them the left endpoint of the first bin is taken as the minimal data value instead of rounded using pretty()
.
spikecomp(1:1000)
spikecomp(1:1000, method='grid')
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