[R] Converting character strings to numeric

[Prof Brian Ripley]

Your minus eight is a hyphen eight, and those will print the same in a 
monospaced font.  As to how you get a hyphen into a string, it depends how 
you do it but I presume this was not entered at an R console.

On Fri, 19 May 2006, Mulholland, Tom wrote:

> I think you are correct (as expected) I don't know where in the original data the string is, but there is other data doing the same thing.
>
> + > strsplit(test," ")[[1]]
> [1] "5159"  "3336"  "3657"  "559"   "3042"  "55"    "307"   "-8"    "16104"
>> as.numeric(strsplit(test," ")[[1]])
> [1]  5159  3336  3657   559  3042    55   307    NA 16104
> Warning message:
> NAs introduced by coercion
>> charToRaw(test)
> [1] 35 31 35 39 20 33 33 33 36 20 33 36 35 37 20 35 35 39 20 33 30 34 32 20 35 35 20 33 30 37 20 96 38 20 31 36 31 30 34
>> test
> [1] "5159 3336 3657 559 3042 55 307 -8 16104"
>> x1 <- "5159 3336 3657 559 3042 55 307 -8 16104"
>> charToRaw(x1)
> [1] 35 31 35 39 20 33 33 33 36 20 33 36 35 37 20 35 35 39 20 33 30 34 32 20 35 35 20 33 30 37 20 2d 38 20 31 36 31 30 34
>> as.numeric(strsplit(x1," ")[[1]])
> [1]  5159  3336  3657   559  3042    55   307    -8 16104
>>
>
> So it looks as if the 96 is throwing it out. I'll dig deeper. I guess 
> there's a bit more pre-Processing to do. The only thing that seems 
> slightly strange is that the small example I made up did not use the 
> original data source, but was typed in the same way I did x1 above. 
> However I can't reproduce the error so it may still be a case of finger 
> trouble on my part.
>
> Tom
>
>> -----Original Message-----
>> From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk]
>> Sent: Friday, 19 May 2006 3:03 PM
>> To: Mulholland, Tom
>> Cc: R-Help (E-mail)
>> Subject: Re: [R] Converting character strings to numeric
>>
>>
>> On Fri, 19 May 2006, Mulholland, Tom wrote:
>>
>>> After replies off the list which indicate the code should
>> work. I tried a variety of approaches.
>>>
>>> Rebooting, Using the --vanilla option and then removing the
>> whole lot and resinstalling. It now works.
>>>
>>> I guess it's another of those windows things?
>>
>> No, it works under Windows.
>>
>> What you have not shown us is x3:
>>
>>> x3
>> [1] "1159"  "1129"  "1124"  "-5"    "-0.44" "-1.52"
>>
>> My guess is that you have something invisible in x1, e.g. a
>> nbspace not a
>> space (although that does not fully explain the results).  What does
>>
>>> charToRaw(x1)
>>   [1] 31 31 35 39 20 31 31 32 39 20 31 31 32 34 20 2d 35 20
>> 2d 30 2e 34 34 20 2d
>> [26] 31 2e 35 32
>>
>> give for you?
>>
>>
>>
>>>
>>> Thanks to those that helped.
>>>
>>>> -----Original Message-----
>>>> From: r-help-bounces at stat.math.ethz.ch
>>>> [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of
>> Mulholland, Tom
>>>> Sent: Friday, 19 May 2006 11:48 AM
>>>> To: R-Help (E-mail)
>>>> Subject: [R] Converting character strings to numeric
>>>>
>>>>
>>>> I assume that I have missed something fundamental and that it
>>>> is there in front of me in "An Introduction to R", but I need
>>>> someone to point me in the right direction.
>>>>
>>>>> x1 <- "1159 1129 1124 -5 -0.44 -1.52"
>>>>> x2 <- c("1159","1129","1124","-5","-0.44","-1.52")
>>>>> x3 <- unlist(strsplit(x1," "))
>>>>>
>>>>>
>>>>> str(x2)
>>>>  chr [1:6] "1159" "1129" "1124" "-5" "-0.44" "-1.52"
>>>>> str(x3)
>>>>  chr [1:6] "1159" "1129" "1124" "-5" "-0.44" "-1.52"
>>>>>
>>>>> as.numeric(x2)
>>>> [1] 1159.00 1129.00 1124.00   -5.00   -0.44   -1.52
>>>>> as.numeric(x3)
>>>> [1] 1159 1129 1124   NA   NA   NA
>>>> Warning message:
>>>> NAs introduced by coercion
>>>>
>>>> What do I have to do to get x3  to be the same as x2.
>>>>
>>>> Tom
>>
>> --
>> Brian D. Ripley,                  ripley at stats.ox.ac.uk
>> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
>> University of Oxford,             Tel:  +44 1865 272861 (self)
>> 1 South Parks Road,                     +44 1865 272866 (PA)
>> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>>
>
>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595