R help - Apr 2011 - Simple question

I am trying to convert a string to a vector, and I'm stuck!

 

Suppose you have a string of numbers (string) that you want to convert to a
vector (vec).  I am able to split the string turning it into a list by using
strsplit, but this makes a list, which I can't seem to access the way that
I'd like to (it becomes a character list of only one(?!?) element.)

 

string<-"1,1,2,3,5,8" 

 

list<-strsplit(string,",")

list # Produces this ugly output with the [[1]] crap which doesn't let me
in!!!!!!!

 

vec<-c(1,1,2,3,5,8)  # All I really want in the end

 

(I'm reading each string from a .csv file using read.csv, so I can't
just
edit my way out of this as my csv file has 200 lines---and counting, if
there is a more elegant way of doing this, let me know, my .csv file has
other values in columns, and each string that I'm reading in has a different
number of elements, so, for example, string2 might be "1,3,5,7,9" and
string3 might be "7".  My bigger problem is that I probably am not
handling
the data.frame object properly.  In other words, I might be so bass-ackward
that I'm doomed to fail without handling the original read-in properly.  A
sample of my .csv file looks like this:

 

Rnum,Cnum,Pnums

1,1,"1,6,7,23,29,31,34,40,45"

1,2,"4,9,22,26,30,38,44,46,47"

1,3,"2,48"

1,4,"3,16,19,41"

1,5,"8,11,12,17,25"

 

)

 

Thanks,

Steven Wolf


	[[alternative HTML version deleted]]

On Apr 19, 2011, at 3:19 PM, Steven Wolf wrote:
> I am trying to convert a string to a vector, and I'm stuck!
>
>
>
> Suppose you have a string of numbers (string) that you want to  
> convert to a
> vector (vec).  I am able to split the string turning it into a list  
> by using
> strsplit, but this makes a list, which I can't seem to access the  
> way that
> I'd like to (it becomes a character list of only one(?!?) element.)
>
> string<-"1,1,2,3,5,8"
>
> list<-strsplit(string,",")
>
> list # Produces this ugly output with the [[1]] crap which doesn't  
> let me
> in!!!!!!!
It produces a list. To return an unlist-ed version, what else?
 > unlist(list)
[1] "1" "1" "2" "3" "5"
"8"

And to make it a numeric vector ... also simple:
 > as.numeric(unlist(list))
[1] 1 1 2 3 5 8
 > vec <- as.numeric(unlist(list))
 > vec == c(1,1,2,3,5,8)
[1] TRUE TRUE TRUE TRUE TRUE TRUE
 > all.equal(vec , c(1,1,2,3,5,8) ) # better practice with numeric  
values
[1] TRUE
 > identical(vec , c(1,1,2,3,5,8) )
  # will not be true in all situations where newbs think it will be
[1] TRUE

-- 
David.


>
> vec<-c(1,1,2,3,5,8)  # All I really want in the end
>
>
>
> (I'm reading each string from a .csv file using read.csv, so I
can't
> just
> edit my way out of this as my csv file has 200 lines---and counting,  
> if
> there is a more elegant way of doing this, let me know, my .csv file  
> has
> other values in columns, and each string that I'm reading in has a  
> different
> number of elements, so, for example, string2 might be "1,3,5,7,9"
and
> string3 might be "7".  My bigger problem is that I probably am
not
> handling
> the data.frame object properly.  In other words, I might be so bass- 
> ackward
> that I'm doomed to fail without handling the original read-in  
> properly.  A
> sample of my .csv file looks like this:
>
>
>
> Rnum,Cnum,Pnums
>
> 1,1,"1,6,7,23,29,31,34,40,45"
>
> 1,2,"4,9,22,26,30,38,44,46,47"
>
> 1,3,"2,48"
>
> 1,4,"3,16,19,41"
>
> 1,5,"8,11,12,17,25"
>
>
>
> )
>
>
>
> Thanks,
>
> Steven Wolf
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
David Winsemius, MD
West Hartford, CT

On 20/04/11 07:19, Steven Wolf wrote:
> I am trying to convert a string to a vector, and I'm stuck!
>
>
>
> Suppose you have a string of numbers (string) that you want to convert to a
> vector (vec).  I am able to split the string turning it into a list by
using
> strsplit, but this makes a list, which I can't seem to access the way
that
> I'd like to (it becomes a character list of only one(?!?) element.)
>
>
>
> string<-"1,1,2,3,5,8"
>
>
>
> list<-strsplit(string,",")
>
> list # Produces this ugly output with the [[1]] crap which doesn't let
me
> in!!!!!!!
>
>
>
> vec<-c(1,1,2,3,5,8)  # All I really want in the end.
<SNIP>

It sounds to me like you don't understand lists.  If you are going to use
R you really should understand them.  They are a wonderfully useful
concept and make doing many otherwise complex tasks an absolute
breeze.  Learn to love lists.  It will be rewarding! :-)

     cheers,

         Rolf Turner