On Oct 20, 2014, at 4:32 AM, PIKAL Petr wrote:
> Hi
>
> Thanks to all who responded.
>
> My input string is rather clumsy. Actually it can have leading or trailing
> empty space too, it can be mixture of positive and negative numbers.
>
> In the meantime I made small function which just strips of - sign and make
> numbers from factors, find numbers which have - sign and change numbers which
> shall be negative to negative. Not as elegant as your solution but works even
> when there are leading or trailing spaces.
>
> zapor <- function(x) {
> num<-as.numeric(gsub("(-)", "", x))
Might want to just use sub() since your method would accept things like
"-----100----"
> zap<- grep("-", x)
> num[zap]<- num[zap] * (-1)
> num}
>
>> x <- as.factor( c(" 123.4- " , " 123 "))
>> zapor(x)
> [1] -123.4 123.0
>>
gsub("^(\\s+)([0-9.]+)(-){0,1}(\\s)+$", "\\3\\2",
as.factor( c(" 123.4- " , " 123 ") ) )
[1] "-123.4" "123"
Then just `as.numeric`. You method looks more elegant. Depending on the local
you may get into trouble with variation in decimal markers.
>
> I just thought that there is some reason for presenting negative numbers with
> minus sign behind the number in finance community and therefore somebody
> already invented clever way how to deal with such numbers.
>
> Cheers
> Petr
>
>
>> -----Original Message-----
>> From: r-help-boun...@r-project.org [mailto:r-help-bounces@r-
>> project.org] On Behalf Of Marc Girondot
>> Sent: Monday, October 20, 2014 12:53 PM
>> To: r-help@r-project.org
>> Subject: Re: [R] format negative numbers
>>
>> Is it what you want?
>>
>>> st <- "0.123-"
>>> gsub("(.+)(-)", "\\2\\1", st)
>> [1] "-0.123"
>>> st <- "0.123"
>>> gsub("(.+)(-)", "\\2\\1", st)
>> [1] "0.123"
>>
>> Sincerely
>> Marc
>>
>> Le 20/10/2014 09:03, PIKAL Petr a écrit :
>>> Dear all.
>>>
>>> Before I start fishing in (for me) murky regular expression waters I
>> try to ask community about changing format of negative numbers.
>>>
>>> For some reason I get a file with negative numbers formatted with
>> negative sign at end of number.
>>>
>>> something like
>>>
>>> 0.123-
>>>
>>> It is imported as factors and I need to convert it to numbers again.
>> Before converting I need to change it to "correct" format
>>>
>>> -0.123
>>>
>>> Does anybody know some simple way?
>>>
>>> Cheers
>>> Petr
>>>
>>>
>>> ________________________________
>>> Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a
>>
David Winsemius
Alameda, CA, USA
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