R help - May 2003 - substitute

Dear r-help,

  I have troubles with 'substitute'.
  I have the data frame with vectors data$area.0, data$area.20, etc...
  Command
  
  substitute(data$area.lon,list(lon=20))

  returns

  data$area.lon

  but is expected to return data$area.20

  Where did I do mistakes?
-- 
Best regards
Wladimir Eremeev                                     mailto:wl at eimb.ru

=========================================================================Research
Scientist                                Leninsky Prospect 33,
Space Monitoring & Ecoinformation Systems Sector, Moscow, Russia, 119071,
Institute of Ecology,                             Phone: (095) 135-9972;
Russian Academy of Sciences                       Fax: (095) 954-5534

On Fri, 16 May 2003, Wladimir Eremeev wrote:
>   I have troubles with 'substitute'.
>   I have the data frame with vectors data$area.0, data$area.20, etc...
>   Command
>   
>   substitute(data$area.lon,list(lon=20))
> 
>   returns
> 
>   data$area.lon
> 
>   but is expected to return data$area.20
> 
>   Where did I do mistakes?
The symbol is area.lon, not lon.  substitute only work on whole symbols, 
and `.' is just part of the alphabet allowed in syntactic names.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595