Re: [R] Converting character strings to numeric

From: Tom Mulholland <tmulholland_at_bigpond.com>
Date: Sat 20 May 2006 - 22:18:30 EST

The data was extracted from a PDF file. I am told by the organization responsible for the data that it is a matter of style. Well now that I know, I can get around it.

Thank you.

Tom

Prof Brian Ripley wrote:

> 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@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@stat.math.ethz.ch
>>>>> [mailto:r-help-bounces@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@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
>>>
>>
>

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