[R] options()$width ignored by print.formula

[Prof Brian Ripley]

On 06/11/2012 17:54, Sarah Goslee wrote:
> Thanks, Prof. Ripley.
>
> Using deparse(b$formula, width.cutoff = options()$width) works as I'd
> expected (full example below). So I can use that to write a custom
> summary.gam(), though that still seems like a lot of work to get
> summary(b) to follow the usual R output conventions.

I think you are misreading the documentation.  ?options says

      ‘width’: controls the maximum number of columns on a line used in
           printing vectors, matrices and arrays, and when filling by
           ‘cat’.

           Columns are normally the same as characters except in CJK
           languages.

Nothing abut language objects there (nor the output from cat(), 
frequently used in print() methods without a 'fill' argument).

Contrast that with deparsing expressions, when 'width.cutoff' is a lower 
rather than upper bound, and is in bytes (not characters nor columns).

As I said, I can see a case from allowing the default cutoff used by 
print() to be under user control, but it would need to be a different 
option from 'width' since it is not even in the same units.

>
> Sarah
>
> library(mgcv)
> # start with example from ?gam
> set.seed(2) ## simulate some data...
> dat <- gamSim(1,n=400,dist="normal",scale=2)
>
> colnames(dat)[1:5] <- c("reallylongnamey", "reallylongnamex0",
> "reallylongnamex1", "reallylongnamex2", "reallylongnamex3")
> b <- gam(reallylongnamey~s(reallylongnamex0)+s(reallylongnamex1)+s(reallylongnamex2)+s(reallylongnamex3),data=dat)
>
> options(width=20)
> deparse(b$formula, width.cutoff = options()$width) # not wrapped to 20
> characters
>
> options(width=150)
> deparse(b$formula, width.cutoff = options()$width) # the formula is
> wrapped even though it fits in the specified width
>
>
> On Tue, Nov 6, 2012 at 12:37 PM, Prof Brian Ripley
> <ripley at stats.ox.ac.uk> wrote:
>> On 06/11/2012 17:01, Sarah Goslee wrote:
>>>
>>> Hi all,
>>>
>>> I'm working with summary.gam() and noticed that the options()$width
>>> argument is ignored by some components of that function, in particular
>>> the formula, which is printed at an arbitrary length regardless of the
>>> desired width.
>>>
>>> I've tracked the problem back to print.formula(), so at a lower level
>>> than summary.gam(). Is there a way around this that I'm missing?
>>
>>
>> Use deparse(): print() on a language type uses (at C level) deparse with the
>> default width.cutoff of 60.  E.g. (subject to vagaries of mailers)
>>
>>> form <-
>>> reallylongnamey~reallylongnamex0+reallylongnamex1+reallylongnamex2+reallylongnamex3
>>> form
>> reallylongnamey ~ reallylongnamex0 + reallylongnamex1 + reallylongnamex2 +
>>      reallylongnamex3
>>> deparse(form, 150)
>> [1] "reallylongnamey ~ reallylongnamex0 + reallylongnamex1 +
>> reallylongnamex2 + reallylongnamex3"
>>
>> I am not sure this is something we would want to make depend on
>> getOption("width"), but it might merit a separate option.
>>
>>>
>>> library(mgcv)
>>> # start with example from ?gam
>>> set.seed(2) ## simulate some data...
>>> dat <- gamSim(1,n=400,dist="normal",scale=2)
>>>
>>>
>>> colnames(dat)[1:5] <- c("reallylongnamey", "reallylongnamex0",
>>> "reallylongnamex1", "reallylongnamex2", "reallylongnamex3")
>>> b <-
>>> gam(reallylongnamey~s(reallylongnamex0)+s(reallylongnamex1)+s(reallylongnamex2)+s(reallylongnamex3),data=dat)
>>>
>>> options(width=20)
>>> b$formula # not wrapped to 20 characters
>>>
>>> options(width=150)
>>> b$formula # the formula is wrapped even though it fits in the specified
>>> width
>>>
>>> # also true for lm()
>>> b <-
>>> lm(reallylongnamey~reallylongnamex0+reallylongnamex1+reallylongnamex2+reallylongnamex3,data=dat)
>>>
>>> options(width=20)
>>> b$call
>>>
>>> options(width=150)
>>> b$call
>>>
>>>
>>> Thanks,
>>> Sarah
>
> --
> Sarah Goslee
> http://www.functionaldiversity.org
>
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>


-- 
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 272866 (PA)
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