[R] Convert a character to numeric

[Boris Steipe]

As there are many possible sources of the warning, to "sort it out" try something like

  which( is.na(<converted-vector>) & (! is.na(<original-vector>)))


B.



> On 2019-04-09, at 11:02, Richard M. Heiberger <rmh using temple.edu> wrote:
> 
> My guess is that numbers formatted with commas are causing an unwanted coercion.
> Remove the commas with gsub before converting to numeric.
> 
>> as.numeric(NA)
> [1] NA
>> as.numeric("1,234,567")
> [1] NA
> Warning message:
> NAs introduced by coercion
>> as.numeric(gsub(",", "", "1,234,567"))
> [1] 1234567
>> 
> 
> On Tue, Apr 9, 2019 at 10:36 AM Alfredo Cortell
> <alfredo.cortell.nicolau using gmail.com> wrote:
>> 
>> Hi Bienvenue,
>> 
>> I believe that your problem is that R can't translate "one" to a number,
>> because it is not a number. R could translate to numeric for example this
>> vector, where numbers are expressed as strings,
>> 
>> c("1","4","7")
>> 
>> but "one" is just letters put together, therefore R can't understand their
>> meaning, and returns NA.
>> 
>> I believe that your best shot is to go with gsub, so that you translate
>> your "string letters" to "string numbers", and then you can do as.numeric
>> no problem
>> 
>> Try this
>> 
>> vec<-c("1",NA,"one")
>> num_vec<-gsub("one",1,vec)
>> num_vec<-as.numeric(num_vec)
>> 
>> Good luck,
>> 
>> Alfredo
>> 
>> 
>> El mar., 9 abr. 2019 a las 15:07, Duncan Murdoch (<murdoch.duncan using gmail.com>)
>> escribió:
>> 
>>> On 09/04/2019 7:30 a.m., Jim Lemon wrote:
>>>> Hi Bienvenue,
>>>> Perhaps you should ask whether you really want to "sort it out". The
>>>> warning is telling you that you are converting the NA values to NA in
>>>> the returned numeric vector.
>>> 
>>> I don't think that's what it is saying.  I think it is saying that a
>>> non-NA value is being converted to NA, because R can't figure out what
>>> number it is.  For example,
>>> 
>>>> as.numeric(c("1", NA))
>>> [1]  1 NA
>>>> as.numeric(c("1", NA, "one"))
>>> [1]  1 NA NA
>>> Warning message:
>>> NAs introduced by coercion
>>> 
>>> 
>>>  I can't think of anything more sensible
>>>> to do with NA values. You may also have character strings that cannot
>>>> be converted into numbers, which will also generate NA values.
>>> 
>>> I think that's the only way that message will appear.
>>> 
>>> Duncan Murdoch
>>> 
>>>  Maybe a
>>>> little example will help us to understand:
>>>> 
>>>> charstr<-c("5","foot","2",NA,"eyes","of","blue")
>>>> as.numeric(charstr)
>>>> [1]  5 NA  2 NA NA NA NA
>>>> 
>>>> Jim
>>>> 
>>>> On Tue, Apr 9, 2019 at 9:16 PM bienvenidozoma using gmail.com
>>>> <bienvenidozoma using gmail.com> wrote:
>>>>> 
>>>>> Hi,
>>>>> 
>>>>> I am applyin function as.numeric to a vector having many values as NA
>>>>> and it is giving :
>>>>> Warning message:
>>>>> NAs introduced by coercion
>>>>> 
>>>>> Can anyone help me to know how to remove this warning and sor it out?
>>>>> 
>>>>> Thanks
>>>>> Bienvenue
>>>>>         [[alternative HTML version deleted]]
>>>>> 
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>>>> 
>>>> ______________________________________________
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>>>> 
>>> 
>>> ______________________________________________
>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>> 
>>        [[alternative HTML version deleted]]
>> 
>> ______________________________________________
>> R-help using 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 using 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.