as.Date (and strptime?) does not recognize "  " as a blank

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(" "))
? [1] c2 a0
? > charToRaw(" ")
? [1] 20
So one can argue that everything works correctly - `textutils` 
function converts HTML's non-breaking space ' ' 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   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 " 2 Mar 2018".