Getting Started

Documentation

Glish

Learn More

Programming

Contact Us

Version 1.9 Build 1488

News	FAQ
Search	Home

sditerator.select - Function

	Package	dish
	Module	dish
	Tool	sditerator

Make a new sditerator by applying a selection criteria record

Synopsis
select(selection)

Description
A new sditerator is constructed by applying the indicated selection criteria record to this sditerator. The returned sditerator is an sditerator which references this sditerator. Only sdrecords which match the criteria are found in the returned sditerator. The returned sditerator may be empty. The structure of the selection criteria record follows the structure of an sdrecord. Only fields which are to be selected on need be included in the selection criteria record. Only scalar fields (strings and numeric fields) in the sdrecord can be part of the criteria. Fields which are measures or quanta records in the sdrecord can be selected if they are single valued. The values used in the selection record should be in the same units as the first sdrecord in this sditerator. For string fields, the selection criteria value for that field should be a vector of values to match during the selection. A simple wildcard can be indicated using an asterisk. For numeric fields, the selection criteria should be a 2-dimensional array of values having dimensions (2, nranges). In other words, this is a set of range pairs. Values in this sditerator for that field which fall within that range or are equal to the range endpoints are considered to match this criteria.

Arguments

selection	in	Selection criteria record
		Allowed:	Glish record
		Default:	[=]

Returns
sditerator tool

Example

   sdit := sditerator('a302_SP');
   sel := [header=[scan_number=array(0,2,3),source_name="UGC1*"]];
   sel.header.scan_number[,1] := [-1, 10];
   sel.header.scan_number[,2] := [15,15];
   sel.header.scan_number[,3] := [50,9999999];
   s2 := sdit.select(sel);

In this example, scan numbers which are less than or equal to 10 or equal to 15 or greater than or equal to 50 are selected, so long as the source name matches the one given in the example (a wild card is used here).