Skip to content

all.equal failure

3 messages · Duncan Murdoch, Terry Therneau

Original
Terry Therneau
# 
This arose in testing [.terms and has me confused.

data(esoph)?? # use a standard data set

t0x <- terms(model.frame( ~ tobgp, data=esoph))
t1 <-? terms(model.frame(ncases ~ agegp + tobgp, data=esoph))
t1x <- (delete.response(t1))[-1]

 > all.equal(t0x, t1x)
[1] TRUE

# the above is wrong, because they actually are not the same

 > all.equal(attr(t0x, 'dataClasses'), attr(t1x, 'dataClasses'))
[1] "Names: 1 string mismatch"
[2] "Lengths (1, 2) differ (string compare on first 1)"

 > sessionInfo()
R Under development (unstable) (2019-04-05 r76323)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 18.04.2 LTS

Matrix products: default
BLAS:?? /usr/local/src/R-devel/lib/libRblas.so
LAPACK: /usr/local/src/R-devel/lib/libRlapack.so

locale:
 ?[1] LC_CTYPE=en_US.UTF-8?????? LC_NUMERIC=C
 ?[3] LC_TIME=en_US.UTF-8??????? LC_COLLATE=C
 ?[5] LC_MONETARY=en_US.UTF-8??? LC_MESSAGES=en_US.UTF-8
 ?[7] LC_PAPER=en_US.UTF-8?????? 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

loaded via a namespace (and not attached):
[1] compiler_3.7.0 tools_3.7.0
Duncan Murdoch
#
On 05/04/2019 9:03 a.m., Therneau, Terry M., Ph.D. via R-devel wrote:
As documented, all.equal() is generic, with methods for different 
classes.  The classes of both t0x and t1x are

  c("terms","formula")

with no all.equal.terms method, so all.equal.formula is called.  That 
method isn't specifically documented, but you can see its definition as

function (target, current, ...)
{
     if (length(target) != length(current))
         return(paste0("target, current differ in having response: ",
             length(target) == 3L, ", ", length(current) == 3L))
     if (!identical(deparse(target), deparse(current)))
         "formulas differ in contents"
     else TRUE
}

So the issue is that deparse(t0x) and deparse(t1x) give the same strings 
with no attributes shown, even though "showAttributes" is set by 
default.   I haven't traced through the C code to see where things are 
going wrong.

Duncan Murdoch
Terry Therneau
# 
Duncan,
 ? I should have included it in my original note, but

 ?? ? all.equal(unclass(t0x), unclass(t1x))

returns TRUE as well.? I had tried that as well. ? But a further look at all.equal.default 
shows the following line right near the top:
 ??? if (is.language(target) || is.function(target))
 ??????? return(all.equal.language(target, current, ...))

and that path explicitly ignores attributes.

I'll change my original original title to "all.equal was not a good tool for testing 
certain code issues".

Thanks for the pointer,

Terry
On 4/5/19 9:00 AM, Duncan Murdoch wrote: