When you what you hope for turns out to
be wrong, then have a look at 'The R Inferno'.
http://www.burns-stat.com/documents/books/the-r-inferno/
It does talk about 'ifelse'.
Pat
On 25/03/2013 02:21, Paul Johnson wrote:
I hope you are doing well.
For me, this was an unexpected problem. I've hoped for quite a few
wrong things today, but I'm only asking you about this one. Why does
ifelse(1, list(a, b, c), list(x, y, z))
return a list with only a, not list(a, b, c) as I hoped. I wish it
would either
cause an error or return the whole list, not just the first thing.
Working example:
x <- 1
y <- 2
z <- 3
a <- 4
b <- 5
c <- 6
list(x,y,z)
[[1]]
[1] 1
[[2]]
[1] 2
[[3]]
[1] 3
list(a,b,c)
[[1]]
[1] 4
[[2]]
[1] 5
[[3]]
[1] 6
ifelse(1, list(a,b,c), list(x,y,z))
[[1]]
[1] 4
ifelse(0, list(a,b,c), list(x,y,z))
[[1]]
[1] 1
sessionInfo()
R version 2.15.3 (2013-03-01)
Platform: x86_64-pc-linux-gnu (64-bit)
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
[7] LC_PAPER=C LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] rockchalk_1.5.5.10 car_2.0-16 nnet_7.3-5 MASS_7.3-23
loaded via a namespace (and not attached):
[1] compiler_2.15.3 tools_2.15.3
I realize I can code around this, but I'm just curious about why
ifelse hates me so much :(
if (1) myvar <- list(a, b, c) else myvar <- list(x, y, z)
myvar
[[1]]
[1] 4
[[2]]
[1] 5
[[3]]
[1] 6
myvar <- if (1) list(a, b, c) else list(x, y, z)
myvar
[[1]]
[1] 4
[[2]]
[1] 5
[[3]]
[1] 6
--
Patrick Burns
pbu...@pburns.seanet.com
twitter: @burnsstat @portfolioprobe
http://www.portfolioprobe.com/blog
http://www.burns-stat.com
(home of:
'Impatient R'
'The R Inferno'
'Tao Te Programming')
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