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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.)  

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