[R] Individual rename of list items

[Prof Brian Ripley]

> From: "Dieter Menne" <dieter.menne at menne-biomed.de>
> Date: Thu, 1 Mar 2001 12:30:20 +0100
> 
> I am confused by the logic of renaming:
> 
> # Rename individual list items?
> 
> Empl<-list(employee="Anna",spouse="Fred")
> names(Empl)<-c("empl","spo")
> names(Empl)
> #[1] "empl" "spo"
> # worked like a charm... but
> 
> names(Empl[1])<-"newempl"
> # no error message, yet ....
> names(Empl)
> #[1] "empl" "spo"
> # where's my newempl???????
> 
> 
> If this line
> 
>   names(Empl[1])<-"newempl"
> 
> was stupid, why is there no error message?

It wasn't stupid,  but it was not what you intended, evidently.  Look at

> Empl[1]
$employee
[1] "Anna"

That is a list, and you gave it a new name, making a new copy. You did
not then reference the new copy.

What you intended I think was

names(Empl)[1]<-"newempl"

which works, but seems not allowed in the R documentation ....

-- 
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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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