[R] Extracting first number after * in a character vector
Jim Lemon
drjimlemon at gmail.com
Mon Jan 23 22:27:22 CET 2017
Hi Abhinaba,
I'm sure that someone will post a terrifyingly elegant regular
expression that does this, but:
ardat<-
c([1] " 1 X[0,SMITH] * 0 0 1 ",
...
numpoststar<-function(x) {
xsplit<-unlist(strsplit(x,""))
starpos<-which(xsplit=="*")
# watch out for a missing asterisk, they cause an infinite loop
if(length(starpos)) {
digits<-c("0","1","2","3","4","5","6","7","8","9")
while(!any(digits %in% xsplit[starpos])) starpos<-starpos+1
return(as.numeric(xsplit[starpos]))
}
return(NA)
}
for(i in 1:length(ardat)) print(numpoststar(ardat[i]))
The observant will wonder why I didn't use sapply. Because for some
reason it returned the original strings rather than the numbers. I
dunno.
Jim
On Mon, Jan 23, 2017 at 11:29 PM, Abhinaba Roy <abhinabaroy09 at gmail.com> wrote:
> Hi,
>
> How do I extract the first number after '*' in a vector?
>
> The vector is given below
>
>> dput(out[1:10])
> c(" 1 X[0,SMITH] * 0 0 1 ",
> " 2 X[0,JOHNSON] * 0 0 1 ",
> " 3 X[0,WILLIAMS]", " * 1 0
> 1 ",
> " 4 X[0,JONES] * 0 0 1 ",
> " 5 X[0,BROWN] * 0 0 1 ",
> " 6 X[0,DAVIS] * 0 0 1 ",
> " 7 X[0,MILLER] * 0 0 1 ",
> " 8 X[0,WILSON] * 0 0 1 ",
> " 9 X[0,MOORE] * 0 0 1 "
> )
>
> I want a vector with the first number after the asterisk.
>
> So the output would give me, a vector (0,0,1,0,0,0,0,0,0,0)
>
> How can I do it in R?
>
> Best,
> Abhinaba
>
> [[alternative HTML version deleted]]
>
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