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

[Bert Gunter]

Thanks, David.

Probably as one should expect.

But reinforces what others said about first doing explicit conversions
so that comparisons are not made made between differing types.

Cheers,
Bert


Bert Gunter

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
   -- Clifford Stoll


On Tue, Nov 17, 2015 at 3:03 PM, David L Carlson <dcarlson at tamu.edu> wrote:
> The conversion seems to be controlled by the scipen setting:
>
>> options("scipen")
> $scipen
> [1] 0
>> as.character(100000)
> [1] "1e+05"
>> options(scipen=5)
>> as.character(100000)
> [1] "100000"
>> as.character(1000000)
> [1] "1000000"
>> as.character(10000000)
> [1] "10000000"
>
> -------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
>
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of peter dalgaard
> Sent: Tuesday, November 17, 2015 3:57 PM
> To: Bert Gunter
> Cc: r-help
> Subject: Re: [R] Strange result when subsetting a data frame based on a character variable
>
>
>> 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
>
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