R help - Sep 2006 - Splitting a character variable into a numeric one and a character one?

Hi All,

I have a data with a variable like this:

Column 1

"123abc"
"12cd34"
"1e23"
...

Now I want to do an operation that can split it into two variables:

Column 1        Column 2         Column 3

"123abc"         123                  "abc"
"12cd34"         12                    "cd34"
"1e23"             1                      "e23"
...

So basically, I want to split the original variabe into a numeric one and a
character one, while the splitting element is the first character in Column
1.

I searched the forum with key words "strsplit"and "substr",
but still can't
solve this problem. Can anyone give me some hints?

Thanks in advance,

FD

	[[alternative HTML version deleted]]

strapply in package gsubfn can do that:


library(gsubfn)
s <- c("123abc", "12cd34", "1e23")

out <- strapply(s, "^([[:digit:]]+)(.*)", c)
out <- do.call(rbind, out) # as a matrix

data.frame(x = out[,1], num = as.numeric(out[,2]), char = out[,3]) #
as a data.frame


On 9/25/06, Frank Duan <fhduan at gmail.com>
wrote:
> Hi All,
>
> I have a data with a variable like this:
>
> Column 1
>
> "123abc"
> "12cd34"
> "1e23"
> ...
>
> Now I want to do an operation that can split it into two variables:
>
> Column 1        Column 2         Column 3
>
> "123abc"         123                  "abc"
> "12cd34"         12                    "cd34"
> "1e23"             1                      "e23"
> ...
>
> So basically, I want to split the original variabe into a numeric one and a
> character one, while the splitting element is the first character in Column
> 1.
>
> I searched the forum with key words "strsplit"and
"substr", but still can't
> solve this problem. Can anyone give me some hints?
>
> Thanks in advance,
>
> FD
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>

On Mon, 2006-09-25 at 11:04 -0500, Frank Duan wrote:
> Hi All,
> 
> I have a data with a variable like this:
> 
> Column 1
> 
> "123abc"
> "12cd34"
> "1e23"
> ...
> 
> Now I want to do an operation that can split it into two variables:
> 
> Column 1        Column 2         Column 3
> 
> "123abc"         123                  "abc"
> "12cd34"         12                    "cd34"
> "1e23"             1                      "e23"
> ...
> 
> So basically, I want to split the original variabe into a numeric one and a
> character one, while the splitting element is the first character in Column
> 1.
> 
> I searched the forum with key words "strsplit"and
"substr", but still can't
> solve this problem. Can anyone give me some hints?
> 
> Thanks in advance,
> 
> FD

Something like this using gsub() should work I think:
> DF
      V1
1 123abc
2 12cd34
3   1e23


# Replace letters and any following chars with ""
DF$V2 <- gsub("[A-Za-Z]+.*", "", DF$V1)


# Replace any initial numbers with ""
DF$V3 <- gsub("^[0-9]+", "", DF$V1)

> DF
      V1  V2   V3
1 123abc 123  abc
2 12cd34  12 cd34
3   1e23   1  e23

See ?gsub and ?regex for more information.

HTH,

Marc Schwartz