From @pencer@gr@ve@ @end|ng |rom prod@y@e@com  Thu Jul  7 14:25:08 2022
From: @pencer@gr@ve@ @end|ng |rom prod@y@e@com (Spencer Graves)
Date: Thu, 7 Jul 2022 07:25:08 -0500
Subject: [Rd] 
 as.Date (and strptime?) does not recognize "&nbsp; " as a blank
In-Reply-To: <9712dcf4-8fd5-cab7-58f6-2ea9fe1e3811@stats.ox.ac.uk>
References: <ffca1662-3ad3-95b0-b5f9-374dffcd0943@prodsyse.com>
 <010201819a8e8fd5-5b4a4be1-e8ab-4b0a-9896-c6d03385dbef-000000@eu-west-1.amazonses.com>
 <3f6da3f4-5eb2-93f6-5c75-c1f35b40edb8@prodsyse.com>
 <9712dcf4-8fd5-cab7-58f6-2ea9fe1e3811@stats.ox.ac.uk>
Message-ID: <32329f15-c09f-b241-fec3-698053ac2234@prodsyse.com>

Thanks, Prof. Ripley, for your further analysis of this issue.  sg


On 7/7/22 6:59 AM, Prof Brian Ripley wrote:
> There is some misunderstanding here.? The space is part of the format 
> specified by SG to as.Date(), which passes it to strptime(). So SG asked 
> to match a space and complained that a different character is not matched!
> 
> Reading the documentation of strptime shows
> 
>  ???? ?%n? Newline on output, arbitrary whitespace on input.
>  ???? ?%t? Tab on output, arbitrary whitespace on input.
> 
> so one might hope that one could use those to specify whitespace instead 
> of ASCII space in the format.? But unfortunately whether a Unicode 
> no-break space (U+00A0) is whitespace is a matter of opinion -- for 
> example the PCRE author changed his a few years back.
> 
> We don't have a reproducible example, but my attempt at reproduction 
> suggests that U+00A0 is not regarded as whitespace on the system I used. 
>  ?We know this to be platform-specific (it uses the C function 
> iswspace): glibc does not regard this as whitespace and the replacement 
> functions used by R on macOS and Windows have followed suit.
> 
> In short, ASCII space matches only itself, and the interpretation of 
> 'blank' (in regexps) or 'whitespace' (in strptime or regexps) is 
> platform-specific and liable to change.
> 
> 
> On 25/06/2022 14:13, Spencer Graves wrote:
>> Hi, Maxim et al.:
>>
>>
>> On 6/25/22 6:10 AM, Maxim Nazarov wrote:
>>> Hello,
>>>
>>>> When is a space not a space?
>>> I guess the answer is when it is a non-breaking one?..
>>>
>>> We can observe:
>>> ? > charToRaw(textutils::HTMLdecode("&nbsp;"))
>>> ? [1] c2 a0
>>> ? > charToRaw(" ")
>>> ? [1] 20
>>> So one can argue that everything works correctly - `textutils` 
>>> function converts HTML's non-breaking space '&nbsp;' into R's 
>>> non-breaking space '\xa0', while %e format of as.Date expects a 
>>> 'normal' space.
>>> But this is obviously not user-friendly especially since both symbols 
>>> are displayed the same way on the console.
>>> So your options might be to either:
>>> ? * manually change all 'weird' spaces into normal ones with 
>>> something like gsub("\\h", " ", ..., perl = TRUE) - for the list of 
>>> other weird spaces see 
>>> https://www.pcre.org/original/doc/html/pcrepattern.html#genericchartypes
>>> ? * persuade textutils author to change &nbsp; into a normal space 
>>> (they seem to be working with a simple lookup table - 
>>> https://github.com/enricoschumann/textutils/blob/b813c7bd4b55daef5fa7612e3fbfe82962711940/R/char_refs.R#L1465-L1466) 
>>>
>>> ? * persuade R-Core (or submit a PR) to relax expectations of 
>>> as.Date/strptime
>>>
>>
>> ?????? Thanks for the reply.? Since "this is obviously not 
>> user-friendly", as you noted, I felt a need to bring it to the 
>> attention of this group, and let them decide what if anything they 
>> would want to do about it.
>>
>>
>> ?????? In any event, I found a fix for my immediate problem.? It's not 
>> as elegant as yours, but it works.
>>
>> ?????? Best Wishes,
>> ?????? Spencer
>>
>>
>>
>>
>>> Kind regards,
>>> Maxim Nazarov
>>>
>>> ----- On Jun 25, 2022, at 8:37 AM, Spencer Graves 
>>> spencer.graves at prodsyse.com wrote:
>>>
>>>> Hello, All:
>>>>
>>>>
>>>> ????? When is a space not a space?
>>>>
>>>>
>>>> ????? Consider the following:
>>>>
>>>>
>>>>> (pblmDate <- textutils::HTMLdecode("&nbsp;2 Mar 2018"))
>>>> [1] " 2 Mar 2018"
>>>>> as.Date(pblmDate, format='%e %b %Y')
>>>> [1] NA
>>>>> as.Date(' 2 Mar 2018', format='%e %b %Y')
>>>> [1] "2018-03-02"
>>>>
>>>>
>>>> ????? Is this a feature or a bug?
>>>>
>>>>
>>>> ????? I can work around it, now that I know what it is, but it took 
>>>> me a
>>>> few hours to diagnose.
>>>>
>>>>
>>>> ????? Thanks,
>>>> ????? Spencer Graves
>>>>
>>>>
>>>> p.s.? I got this from scraping a website with code that had worked for
>>>> me roughly 20 months ago.? I suspect that in the interim, someone
>>>> probably replaced ' 2 Mar 2018' with "&nbsp;2 Mar 2018".
>>>>
>>>> ______________________________________________
>>>> R-devel at r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
> 
>



[Rd] as.Date (and strptime?) does not recognize "&nbsp; " as a blank
Spencer Graves