selectSome: Extract elements of a vector for concise rendering
Description
Extract the first and last several elements of a vector for concise
rendering; insert ellipses to indicate elided elements. This function
is primarily meant for developer rather than end-user use.
Usage
selectSome(obj, maxToShow=5)
Arguments
obj
A vector.
maxToShow
The number of elements (including "...") to render.
Value
A string vector with at most maxToShow plus 1 elements,
where an ellipsis ("...") is included to indicate incompleteness
of the excerpt.
Details
This function can be used in 'show' methods to give users exemplars of
the tokens used in a vector. For example, an
ExpressionSet built from a yeast experiment might have
features enumerated using systematic gene names (e.g., YPR181C) or
standard gene names (e.g., SEC23). The show method for
ExpressionSet uses selectSome to alert the user to
the tokens used, and thereby to indicate what vocabulary must be
understood to work with the feature names.