[R] Bug or feature with finding a list element?

[Patrick Burns]

I think you will find that this follows the partial
matching rules:

* exact match
* unique partial match
* take evasive action if non-unique partial match

Patrick Burns
patrick at burns-stat.com
+44 (0)20 8525 0696
http://www.burns-stat.com
(home of S Poetry and "A Guide for the Unwilling S User")

B Fox wrote:
> This seems odd.  When I try to look up a list element which has a space in
> the name using just the first word (i.e. no spaces), it will sometimes
> return the element with a space in the name and sometimes it will return
> NULL.
>
> Try this:
>
> alist <- list( 'hello'=10, bye=20, 'hello world'=30, 'goodbye world'=40, 'hi
> world'=50, 'goodbye foo'=60, 'goodbye bar'=70)
> Then try fetching some list elements:
>   
>> alist[['goodbye']]
>>     
> NULL
>   
>> alist[['hi']]
>>     
> [1] 50
>   
>> alist[['hello']]
>>     
> [1] 10
> With "goodbye" there were a couple list elements with spaces in the name, so
> it didn't return any of them.
>
> With "hi" there was one (and only one) element which had "hi" as the first
> word: "hi world"
>
> With "hello" there was an actual element named "hello"
>
> This seems messed up and non-intuitive to say the least.
>
> I am doing this on R version 2.5.0 (2007-04-23) compiled on a itanium64
> and I also tried it on R version 2.5.1 (2007-06-27) on an pentium 4 ubuntu
> linux
>
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