[R] parsing numeric values

[baptiste auguie]

Thanks a lot, both of you.

Incidentally, I made R crash when I forgot the X argument to strapply,

library(gsubfn)
Loading required package: tcltk
Loading Tcl/Tk interface ... done
strapply("test", as.numeric)

 *** caught bus error ***
address 0x13c, cause 'non-existent physical address'

Traceback:
 1: .External("dotTclcallback", ..., PACKAGE = "tcltk")
 2: .Tcl.callback(x, e)
 3: makeAtomicCallback(x, e)
 4: makeCallback(get("value", envir = ref), get("envir", envir = ref))
 5: FUN(X[[3L]], ...)
 6: lapply(val, val2obj)
 7: .Tcl.args.objv(...)
 8: structure(.External("dotTclObjv", objv, PACKAGE = "tcltk"), class
= "tclObj")
 9: .Tcl.objv(.Tcl.args.objv(...))
10: tcl("set", "e", e)
11: strapply1(x, pattern, backref, ignore.case)
12: FUN("test"[[1L]], ...)
13: lapply(X, FUN, ...)
14: sapply(X, ff, simplify = is.logical(simplify) && simplify,
USE.NAMES = USE.NAMES)
15: strapply("test", as.numeric)

Possible actions:
1: abort (with core dump, if enabled)
2: normal R exit
3: exit R without saving workspace
4: exit R saving workspace

sessionInfo()
R version 2.10.0 (2009-10-26)
i386-apple-darwin9.8.0

locale:
[1] en_GB.UTF-8/en_GB.UTF-8/C/C/en_GB.UTF-8/en_GB.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  grid      methods
[8] base

other attached packages:
[1] ggplot2_0.8.3  reshape_0.8.3  plyr_0.1.9     proto_0.3-8    fortunes_1.3-6

2009/11/18 Gabor Grothendieck <ggrothendieck at gmail.com>:
> A minor variant might be the following:
>
>   library(gsubfn)
>   strapply(input, "\\d+\\.\\d+E[-+]?\\d+", as.numeric, simplify = rbind)
>
> where:
>
> - as.numeric is used in place of c in which case we do not need combine
> - \\d+ matches one or more digits
> - \\. matches a decimal point
> - [-+]? matches -, + or nothing (i.e. an optional sign).
> - parentheses around the regular expression not needed
>
> On Wed, Nov 18, 2009 at 7:28 AM, Henrique Dallazuanna <wwwhsd at gmail.com> wrote:
>> Try this:
>>
>> strapply(input, "([0-9]+\\.[0-9]+E-[0-9]+)", c, simplify = rbind,
>> combine = as.numeric)
>>
>> On Wed, Nov 18, 2009 at 9:57 AM, baptiste auguie
>> <baptiste.auguie at googlemail.com> wrote:
>>> Dear list,
>>>
>>> I'm seeking advice to extract some numeric values from a log file
>>> created by an external program. Consider the following example,
>>>
>>> input <-
>>> readLines(textConnection(
>>> "some text
>>>  <ax> =    1.3770E-03     <bx> =    3.4644E-07
>>>  <ay> =    1.9412E-04     <by> =    4.8840E-08
>>>
>>> other text
>>>  <aax>  =    1.3770E-03     <bbx> =    3.4644E-07
>>>  <aay>  =    1.9412E-04     <bby> =    4.8840E-08"))
>>>
>>> ## this is what I want
>>> results <- c(as.numeric(strsplit(grep("<ax>", input,val=T), " ")[[1]][8]),
>>>             as.numeric(strsplit(grep("<ay>", input,val=T), " ")[[1]][8]),
>>>             as.numeric(strsplit(grep("<aax>", input,val=T), " ")[[1]][9]),
>>>             as.numeric(strsplit(grep("<aay>", input,val=T), " ")[[1]][9])
>>>             )
>>>
>>> ## [1] 0.00137700 0.00019412 0.00137700 0.00019412
>>>
>>> The use of strsplit is not ideal here as there is a different number
>>> of space characters in the lines containing <ax> and <aax> for
>>> instance (hence the indices 8 and 9 respectively).
>>>
>>> I tried to use gsubfn for a cleaner construct,
>>>
>>> strapply(input, "<ax> += +([0-9.]+)", c, simplify=rbind,combine=as.numeric)
>>>
>>> but I can't seem to find the correct regular expression to deal with
>>> the exponent.
>>>
>>>
>>> Any tips are welcome!
>>>
>>>
>>> Best regards,
>>>
>>> baptiste
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> 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.
>>>
>>
>>
>>
>> --
>> Henrique Dallazuanna
>> Curitiba-Paraná-Brasil
>> 25° 25' 40" S 49° 16' 22" O
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> 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.
>>
>