[R] Significant digits for checking values of variable?

[jim holtman]

Try this using 'sapply'"

> sapply(X.new, all.equal, .2) == "TRUE"
[1]  TRUE FALSE


On Wed, Aug 27, 2008 at 12:13 PM, David Afshartous
<dafshartous at med.miami.edu> wrote:
>
> Thanks.  Is there simple way around this for simple checking of single
> values?  The all.equal() mentioned in the FAQ doesn't seem appropriate.
>
>  X = c(1.2, 2)
>> X.new = X -1
>> X == 1.2
> [1]  TRUE FALSE
>> X.new == .2
> [1] FALSE FALSE
>
>
>
> On 8/27/08 11:47 AM, "jim holtman" <jholtman at gmail.com> wrote:
>
>> FAQ 7.31
>>
>> On Wed, Aug 27, 2008 at 11:51 AM, David Afshartous
>> <dafshartous at med.miami.edu> wrote:
>>>
>>> All,
>>>
>>> I'm witnessing some strange behavior when checking the values of one of my
>>> variables.  My guess is that it has something to do with the number of
>>> significant digits being represented, but perhaps not as my variable was
>>> created from other variables that only had one decimal place.  See below.
>>> I'm sure this is something basic, any suggestions much appreciated.
>>>
>>> Cheers,
>>> David
>>>
>>>
>>>> visit.2.SEK.delta.baseline
>>>  [1]  0.1 -0.7  0.8 -0.1 -0.5  0.8  0.7  0.2  0.4  0.3  0.6  0.6  0.3  0.8
>>> 0.8  0.3  0.4  0.8
>>>> visit.2.SEK.delta.baseline > 0
>>>  [1]  TRUE FALSE  TRUE FALSE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE
>>> TRUE  TRUE  TRUE  TRUE  TRUE  TRUE
>>>> visit.2.SEK.delta.baseline ==  .8
>>>  [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
>>> FALSE FALSE FALSE FALSE FALSE FALSE
>>> ### but some of the values are equal to .8
>>>
>>> ## here it is okay when I try to reproduce
>>>>  junk = c(0.1, -0.7,0.8, -0.1, -0.5,  0.8,  0.7,  0.2,  0.4,  0.3,  0.6,
>>>> 0.6,
>>> 0.3,  0.8,  0.8,  0.3,  0.4,  0.8 )
>>>> junk == .8
>>>  [1] FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE
>>> FALSE  TRUE  TRUE FALSE FALSE  TRUE
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>>
>
>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?