[R] Strange result when subsetting a data frame based on a character variable

[peter dalgaard]

> On 18 Nov 2015, at 01:59 , Jeff Newmiller <jdnewmil at dcn.davis.CA.us> wrote:
> 
> Are you sure that wasn't oh-3 rather than 03?

Sure I'm sure. I even cut+pasted the filenames from the offending dir... It's all just Apple trying to be helpful (and failing, again).

O2 < 2d < O3 had been even stranger, no?

-p

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> Sent from my phone. Please excuse my brevity.
> 
> On November 17, 2015 1:57:15 PM PST, peter dalgaard <pdalgd at gmail.com> wrote:
>> 
>>> On 17 Nov 2015, at 20:37 , Bert Gunter <bgunter.4567 at gmail.com>
>> wrote:
>>> 
>>>> 2 == "2"
>>> [1] TRUE
>>> 
>>> ?"=="  says:
>>> 
>>> "If the two arguments are atomic vectors of different types, one is
>>> coerced to the type of the other, the (decreasing) order of
>> precedence
>>> being character, complex, numeric, integer, logical and raw."
>>> 
>>>> as.character(99999)
>>> [1] "99999"
>>>> as.character(100000)
>>> [1] "1e+05"
>>>> as.character(100000) == "100000"
>>> [1] FALSE
>>> 
>> 
>> Also notice that, for similar reasons
>> 
>>> 10 > "2"
>> [1] FALSE
>> 
>> (At least in most collations. I recently discovered that OSX Finder
>> sorted 2dnorm.R between 02-Probability.toc and
>> 03-Combinatorics-2x2.pdf.)	
> 

-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com