[R] Matching/checking for occurence when values are double?

[ruipbarradas at sapo.pt]

Not exactly, all.equal is much more complete.
It accepts all kinds of objects, not just vectors.


Rui Barradas


Citando Ivan Calandra <ivan.calandra at univ-reims.fr>:

> Hi,
>
> Not sure, but it seems that your function equal() is exactly what  
> all.equal() does, isn't it?
>
> Ivan
>
> --
> Ivan Calandra, PhD
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> University of Reims Champagne-Ardenne
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>
> Le 09/09/2016 à 14:47, ruipbarradas at sapo.pt a écrit :
>> Hello,
>>
>> See FAQ 7.31.
>> It's irrelevant if you write 100 or 100.0, the values are the same.  
>> The difference would be between 100 (double) and 100L (integer).
>> To check for equality between floating-point numbers you can use,  
>> for instance, the following function.
>>
>> equal <- function(x, y, eps = .Machine$double.eps^0.5) abs(x - y) < eps
>>
>> equal(100, 100 + 2e-15)
>> [1] TRUE
>>
>> Hope this helps,
>>
>> Rui Barradas
>>
>>
>>
>> Citando Matti Viljamaa <mviljamaa at kapsi.fi>:
>>
>>> I need to pick from a dataset those rows that have a double value  
>>> set to 100.
>>> However since the values in this column are like the following:
>>>
>>> [1] 121.11750  89.36188 115.44320  99.44964  92.74571 107.90180
>>> [7] 138.89310 125.14510  81.61953  95.07307  88.57700  94.85971
>>> [13]  88.96280 114.11430 100.53410 120.41910 114.42690
>>> …
>>>
>>> Then can I match against 100 or 100.0? Or do I need to match  
>>> against 100.00000 or something else?
>>>
>>> E.g. does
>>>
>>> 100.0 %in% kidmomiq$mom_iq
>>>
>>> produce a truthful match result with this kind of data (I’m  
>>> getting 0 occurrences, which might be correct, but I’m not sure)?
>>> ______________________________________________
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>>> PLEASE do read the posting guide  
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.