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KeyMap - Store a set of key/value pairs

Description:
The KeyMap class is used to store a set of values with associated keys which identify the values. The keys are strings. These may be case sensitive or insensitive as selected by the KeyCase attribute, and trailing spaces are ignored. The value associated with a key can be integer (signed 4 and 2 byte, or unsigned 1 byte), floating point (single or double precision), character string or AST Object pointer. Each value can be a scalar or a one-dimensional vector. A KeyMap is conceptually similar to a Mapping in that a KeyMap transforms an input into an output - the input is the key, and the output is the value associated with the key. However, this is only a conceptual similarity, and it should be noted that the KeyMap class inherits from the Object class rather than the Mapping class. The methods of the Mapping class cannot be used with a KeyMap.
Constructor Function:
AST_KEYMAP
Inheritance
The KeyMap class inherits from the Object class.
Attributes
In addition to those attributes common to all Objects, every KeyMap also has the following attributes:

  • KeyCase: Sets the case in which keys are stored

  • KeyError: Report an error if the requested key does not exist?

  • SizeGuess: The expected size of the KeyMap.

  • SortBy: Determines how keys are sorted in a KeyMap.

  • MapLocked: Prevent new entries being added to the KeyMap?
Functions
In addition to those routines applicable to all Objects, the following routines may also be applied to all KeyMaps:



next up previous 264
Next: LutMap - Transform 1-dimensional coordinates using a lookup table
Up: AST Class Descriptions
Previous: IntraMap - Map points using a private transformation routine

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2009 Science \& Technology Facilities Council