Method and apparatus for displaying on computer display device a portion of sorted list and corresponding indicator of location within list

This invention provides a method and apparatus for displaying on a computer display device both a portion of a sorted list of unknown length having a plurality of items and an indicator which is a corresponding approximation of a location of the portion within the list. For a sorted list, keys pertaining to a characteristic used to sort the list are assigned key order values which are indicator values corresponding to a current position within the list. The first key and last key in the list are used to determine a range of values for the indicator. Keys may be arranged in groupings. In that case the keys within a particular grouping are mapped to the same key order value. Preferably, groupings are defined according to a statistical probability of occurrence of the members of the grouping such that each grouping has substantially the same statistical probability of occurring. Preferably, the mapping of keys or groupings is stored in a table such that given a particular key or grouping, an associated indicator value may be found and, likewise, that given a particular indicator value, an associated key or grouping may be found. The indicator reflects a relative location of a portion of the list being displayed with respect to the entire list. When a display of the list changes such that an item of a new key or grouping is being displayed, the display of the indicator changes to reflect the new positioning within the list. If a user changes the position of the indicator, a portion of the list approximately relating to the new indicator position is displayed in the display area.