[Rd] "with" doesn't work with names with blanks

[Spencer Graves]

On 5/1/22 2:51 PM, Duncan Murdoch wrote:
> On 01/05/2022 3:41 p.m., Spencer Graves wrote:
>> Hello, All:
>>
>>
>>       Column names in a data.frame are not supposed to have trailing
>> blanks.  However, a CRAN package created one, which threw an error with
>> "with".  Consider the following example:
>>
>>
>>   > (tst <- data.frame(1))
>>     X1
>> 1  1
>>   > names(tst) <- 'x '
>>   > tst$x
>> [1] 1
>>   > with(tst, x)
>> Error in eval(substitute(expr), data, enclos = parent.frame()) : 
   object 'x' not found>>
>>
>>       I think it's interesting that "tst$x" works, but "with(txt, x)".
>>
>>
>>       Comments?
> 
> tst$x works because of partial name matching.  (That leniency is one of 
> the reasons for advice to avoid using $ in programs.)  It would be chaos 
> if with() used partial name matching.
> 
> You can use
> 
> with(txt, `x `)
> 
> to include the space in the name.


but to use that, I have to KNOW that the name is `x `, not `x`.  It took 
me a while to identify that as the source of the problem:  What I saw 
was that "with(tst


	  And thanks for the reminder that you recommend avoiding use of "$".


	  sg


p.s.  After I found the problem, I fixed it using
names(x) <- tis::stripBlanks(names(x))

> 
> Duncan Murdoch
> 
>>
>>
>>       It's not a major problem, though it took me a while to 
>> diagnose.  (I
>> reported it to the maintainer of the package that returned a data.frame
>> with names with trailing blanks.)
>>
>>
>>       Thanks, for all your work in maintaining and upgrading R -- and in
>> responding to emails from this list.
>>
>>
>>       Spencer Graves
>>
>>
>>   > sessionInfo()
>> R version 4.2.0 (2022-04-22)
>> Platform: x86_64-apple-darwin17.0 (64-bit)
>> Running under: macOS Big Sur 11.6.5
>>
>> Matrix products: default
>> LAPACK:
>> /Library/Frameworks/R.framework/Versions/4.2/Resources/lib/libRlapack.dylib 
>>
>>
>> locale:
>> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>>
>> attached base packages:
>> [1] stats     graphics  grDevices utils     datasets  methods   base
>>
>> loaded via a namespace (and not attached):
>> [1] compiler_4.2.0 tools_4.2.0
>>   >
>>
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>