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

[Ivan Calandra]

Hi,

Not sure, but it seems that your function equal() is exactly what 
all.equal() does, isn't it?

Ivan

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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)?
>> ______________________________________________
>> 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.