another way to do it is using eval and parse:

yyy<-numeric()
for(i in 1:length(xxx)) yyy[i] <- eval(parse(text=xxx[i]))

or ...

unlist(lapply(as.list(xxx), function(x) eval(parse(text=x))))

then xxx can contain any valid expressions (not necessarily fractions)

Kenn

On Sat, Jun 21, 2008 at 12:44 PM, Hans-Jörg Bibiko <bibiko@eva.mpg.de>
wrote:

>
> On 21.06.2008, at 01:36, Ken Liu wrote:
>
>> I would like to convert a character vector
>>
>> xxx <- c("1/2", "1/4")
>>
>> to
>>
>> yyy <- c(0.5, 0.25)
>>
>>
>> , but as.numeric didn't work for me.  Could anyone give me a hint please?
>>
>
> There are many many ways, and they're depending on the structure of xxx. If
> you only have such fractions you can use this naïve approach:
>
> as.numeric( gsub("(\\d+)/(\\d+)", "\\1", xxx, perl=T) ) / as.numeric(
> gsub("(\\d+)/(\\d+)", "\\2", xxx, perl=T) )
>
> --Hans
>
>
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>

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