If an argument is specified in the help text for a
command with the symbol <col-id>
it means you must give a string which identifies one of the
existing columns in a table.
There are three ways you can specify a column in this context:
-
').
It is usually matched case insensitively. If multiple columns
have the same name, the first one that matches is selected.
Tip: if counting which column has which index is giving you a
headache, running tpipe
with omode=meta
or
omode=stats
on the table may help.
ucd$<ucd-spec>
". Depending on the version of
UCD scheme used, UCDs can contain various punctuation marks such
as underscores, semicolons and dots; for the purpose of this syntax
these should all be represented as underscores ("_
").
So to identify a column which has the UCD "phot.mag;em.opt.R
",
you should use the identifier "ucd$phot_mag_em_opt_r
".
Matching is not case-sensitive. Futhermore, a trailing underscore
acts as a wildcard, so that the above column could also be referenced
using the identifier "ucd$phot_mag_
". If multiple
columns have UCDs which match the given identifer, the first one
will be used.