[Rd] hash access to data.frame uses prefix? (PR#10474)

From: <pkensche_at_cmbi.ru.nl>
Date: Wed, 28 Nov 2007 09:25:31 +0100 (CET)


Full_Name: Philip Kensche
Version: R version 2.5.0 (2007-04-23)
OS: Linux
Submission from: (NULL) (131.174.146.31)

I want to access a row of a data.frame() by using the row names as hash keys. This works fine for most keys.

Now consider the following data.frame().

> x <- data.frame(v=c(V40="a", V411="b"))

> x

     v
V40 a
V411 b

If I query for "V41", which does not exist in the data.frame() the call does not return NA as I would expect but the row "V411".

> x[ "V41", ]

[1] b
Levels: a b

If there the prefix is not unique the query does not return a results, i.e.

> x <- data.frame(v=c(V412="a", V411="b"))

> x

     v
V412 a
V411 b

> x[ "V41", ]

[1] <NA>
Levels: a b

sessionInfo() output:
> sessionInfo()

R version 2.5.0 (2007-04-23)

i686-pc-linux-gnu

locale:
LC_CTYPE=en_US;LC_NUMERIC=C;LC_TIME=en_US;LC_COLLATE=en_US;LC_MONETARY=en_US;LC_MESSAGES=en_US;LC_PAPER=en_US;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US;LC_IDENTIFICATION=C

attached base packages:
[1] "stats" "graphics" "grDevices" "utils" "datasets" "methods" [7] "base"

other attached packages:
 lattice
"0.15-4"



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