NRAO Home > CASA > CASA Toolkit Reference Manual
ms.msseltoindex - Function

1.3.1 Returns ids of the selection used


Description

Utility function that will return the ids of the selection used.

Arguments





Inputs

vis

Measurementset for which this selection applies

allowed:

string

Default:

spw

Spectral Window Ids (0 relative) to select; -1 interpreted as all

allowed:

any

Default:

variant

field

Field Ids (0 relative) or Field names (msselection syntax and wilcards are used) to select

allowed:

any

Default:

variantvariant

baseline

Antenna Ids (0 relative) or Antenna names (msselection syntax and wilcards are used) to select

allowed:

any

Default:

variant

time

Limit data selected to be within a given time range. Syntax is the defined in the msselection link

allowed:

any

Default:

variant

scan

Limit data selected on scan numbers. Syntax is the defined in the msselection link

allowed:

any

Default:

variant

uvrange

Limit data selected on uv distance. Syntax is the defined in the msselection link

allowed:

any

Default:

variant

observation

Select data by observation ID(s). The syntax is the same as for scan numbers.

allowed:

any

Default:

variant

polarization

Select data by polarization(s).

allowed:

any

Default:

variant

taql

For the TAQL experts, flexible data selection using the TAQL syntax

allowed:

string

Default:

Returns
record

Example

 
     a= ms.msseltoindex(vis=’3C273XC1.MS’, field=’3C*’)  
     print a[’field’]  
     # [0]  
     print a  
     #{’antenna1’: array([], dtype=int32),  
     # ’antenna2’: array([], dtype=int32),  
     #  ’channel’: array([], shape=(0, 0), dtype=int32),  
     #  ’field’: array([0]),  
     #  ’scan’: array([], dtype=int32),  
     #  ’spw’: array([], dtype=int32),  
     #  ’obsids’: array([], dtype=int32)}  
 
 
  Field name ’3C*’, in this case 3C273, corresponds to field id 0.  
 
  N.B.: The return values of unspecified fields (like antenna* and spw in the  
        above example) will be left empty - this does not mean that selection  
        excludes all antennas!  
 
        Some fields (like ’field’) are checked against the subtables of vis,  
        but others are not.  For example, field=’123~132’ will produce an error  
        if vis does not have fields 123 to 132, but for scan and obsids  
        ’123~132’ would just return an array of integers from 123 to 132  
        regardless of whether vis has those scan or observation IDs.  (The  
        difference comes from it being quicker to check a subtable than the  
        main table.)  

__________________________________________________________________


More information about CASA may be found at the CASA web page

Copyright 2016 Associated Universities Inc., Washington, D.C.

This code is available under the terms of the GNU General Public Lincense


Home | Contact Us | Directories | Site Map | Help | Privacy Policy | Search