breaksByVector: break a vector into groups

In jmw86069/jamba: Jam Base Methods

break a vector into groups

Description

breaks a vector into groups

Usage

breaksByVector(x, labels = NULL, returnFractions = FALSE, ...)

Arguments

x	character vector of labels
labels	character vector of custom labels to represent the items in x
returnFractions	logical whether to return fractional coordinates for labels that should be positioned between two labels
...	additional parameters are ignored.

Details

This function takes a vector of values, determines "chunks" of identical values, from which it defines where breaks occur. It assumes the input vector is ordered in the way it will be displayed, with some labels being duplicated consecutively. This function defines the breakpoints where the labels change, and returns the ideal position to put a single label to represent a duplicated consecutive set of labels.

It can return fractional coordinates, for example when a label represents two consecutive items, the fractional coordinate can be used to place the label between the two items.

This function is useful for things like adding labels to imageDefault() color image map of sample groupings, where it may be ideal to label only unique elements in a contiguous set.

Value

list with the following named elements:

• "breakPoints"The mid-point coordinate between each break. These midpoints would be good for drawing dividing lines for example.

• "labelPoints"The ideal point to place a label to represent the group.

• "newLabels"A vector of labels the same length as the input data, except using blank values except where a label should be drawn. This output is good for text display.

• "useLabels"The unique set of labels, without blanks, corresponding to the coordinates supplied by labelPoints.

• "breakLengths"The integer size of each set of labels.

See Also

Other jam string functions: asSize(), cPasteSU(), cPasteS(), cPasteUnique(), cPasteU(), cPaste(), fillBlanks(), formatInt(), gsubOrdered(), gsubs(), makeNames(), mixedOrder(), mixedSortDF(), mixedSorts(), mixedSort(), mmixedOrder(), nameVectorN(), nameVector(), padInteger(), padString(), pasteByRowOrdered(), pasteByRow(), sizeAsNum(), tcount(), ucfirst(), uniques()

Examples

b <- rep(LETTERS[c(1:5, 1)], c(2,3,5,4,3,4));
bb <- breaksByVector(b);
# Example showing how labels can be minimized inside a data.frame
data.frame(b,
   newLabels=bb$newLabels);

# Example showing how to reposition text labels
# so duplicated labels are displayed in the middle
# of each group
bb2 <- breaksByVector(b, returnFractions=TRUE);
ylabs <- c("minimal labels", "all labels");
adjustAxisLabelMargins(ylabs, 2);
adjustAxisLabelMargins(bb2$useLabels, 1);
nullPlot(xlim=range(seq_along(b)), ylim=c(0,3),
   doBoxes=FALSE, doUsrBox=TRUE);
axis(2, las=2, at=c(1,2), ylabs);
text(y=2, x=seq_along(b), b);
text(y=1, x=bb2$labelPoints, bb2$useLabels);

## Print axis labels in the center of each group
axis(3,
   las=2,
   at=bb2$labelPoints,
   labels=bb2$useLabels);

## indicate each region
for (i in seq_along(bb2$breakPoints)) {
   axis(1,
      at=c(c(0, bb2$breakPoints)[i]+0.8, bb2$breakPoints[i]+0.2),
      labels=c("", ""));
}
## place the label centered in each region without adding tick marks
axis(1,
   las=2,
   tick=FALSE,
   at=bb2$labelPoints,
   labels=bb2$useLabels);
## abline to indicate the boundaries, if needed
abline(v=c(0, bb2$breakPoints) + 0.5,
   lty="dashed",
   col="blue");

# The same process is used by imageByColors()

jmw86069/jamba documentation built on March 26, 2024, 5:26 a.m.