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strptime and "impossible" dates

2 messages · a296180 at mica.fmr.com (David Kane, Brian Ripley

Original
a296180 at mica.fmr.com (David Kane
# 
Typically, when I use strptime with "impossible" dates I get an NA, which is
what I expect.
_                   
platform sparc-sun-solaris2.6
arch     sparc               
os       solaris2.6          
system   sparc, solaris2.6   
status                       
major    1                   
minor    3.0                 
year     2001                
month    06                  
day      22                  
language R
[1] "NA"

But this is not always the case, consider the impossible case of November 31, 2000
[1] "2000-12-01"

Shouldn't the answer here be NA? I would submit this as a bug except that I
suspect that the problem is my misunderstanding of the role of seconds and time
zones is this function . . .

Thanks for any pointers. I have read the help pages and the excellent
discussion in the recent R Newsletter.

Dave Kane
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Brian Ripley
#
On Tue, 24 Jul 2001, David Kane <David Kane wrote:

            

      
      
      
    

        
It depends on the system's strptime.  But it would be usual for
out-of-range dates to get normalized as you saw.  In general `invalid'
local times (POSIXlt structures) are fixed if they are not seriously
adrift.