General selection syntax

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2.3.1 General selection syntax

Most of the selections are effected through the use of selection strings. This sub-section describes the general rules used in constructing and parsing these strings. Note that some selections are done though the use of numbers or lists. There are also parameter-specific rules that are described under each parameter.

All lists of basic selection specification-units are comma separated lists and can be of any length. White-spaces before and after the commas (e.g. ’3C286, 3C48, 3C84’) are ignored, while white-space within sub-strings is treated as part of the sub-string (e.g. ’3C286, VIRGO A, 3C84’).

All integers can be of any length (in terms of characters) composed of the characters 0–9. Floating point numbers can be in the standard format (DIGIT.DIGIT, DIGIT., or .DIGIT) or in the mantissa-exponent format (e.g. 1.4e9). Places where only integers make sense (e.g. IDs), if a floating point number is given, only the integer part is used (it is truncated).

Range of numbers (integers or real numbers) can be given in the format ’N0~N1’. For integer ranges, it is expanded into a list of integers starting from N0 (inclusive) to N1 (inclusive). For real numbers, it is used to select all values present for the appropriate parameter in the Measurement Set between N0 and N1 (including the boundaries). Note that the ’~’ character is used rather than the more obvious ’-’ in order to accommodate hyphens in strings and minus signs in numbers.

Wherever appropriate, units can be specified. The units are used to convert the values given to the units used in the Measurement Set. For ranges, the unit is specified only once (at the end) and applies to both the range boundaries.

2.3.1.1 String Matching

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