[R] Converting character strings to numeric

[Mulholland, Tom]

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
>