thselect: Select tables satisfying an expression; print keywords.

Package: nttools

Usage

thselect table keywords expr

Description

This task was based on 'hselect', and it behaves in a very similar manner, except that it works on tables rather than images.

Keyword values will be printed to the standard output, one line per input table, with the values separated by tabs. String values that contain whitespace will be enclosed in quotes.

Parameters

table [file name template]: A list of tables for which keywords are to be printed. These will be opened read-only and will not be modified.

keywords [string]: One or more keywords, separated by commas and/or blanks. The special keywords such as "i_table" that are supported by 'thedit' can also be used with 'thselect'. For each input table, the values of these keywords in the current input table will be printed, if 'expr' is a true expression for the current table. Any keyword that is not found will be silently ignored. Wildcards are supported; however, the "@filename" syntax is not supported.

expr = "yes" [string]: This is a boolean expression to be evaluated for each table in the list. The default value may be used to unconditionally print keyword values. The expression may include constants and/or keyword names.

Examples

1. Compare 'thselect' with 'thedit' for displaying a single keyword value.

tt> thselect timetag.fits[events,7] rootname yes

O57P03030

tt> thedit timetag.fits[events,7] rootname .

timetag.fits[events,7],ROOTNAME = O57P03030 / rootname of the obser
vation set

2. Compare i_file with i_table for a FITS table ($I and i_table are equivalent).

tt> thselect timetag.fits[events,7] i_file,i_table yes

timetag.fits      timetag.fits[EVENTS,7]

3. Find all FITS files with DETECTOR = 'CCD' in the primary header. Since the primary header of a FITS file can be opened either as an image or as a table, either 'hselect' or 'thselect' could be used for this example.

tt> thselect *.fits[0] $I "detector == 'CCD'"

h1v11148o_1dx.fits[0]
h4s13500o_1dx.fits[0]
i1c1615po_1dx.fits[0]

Bugs

References

This task was written by Phil Hodge, based on 'hselect'.