R help - Jul 2011 - Substring a column vector

How to substring the following vector (in data frame b)
>b
a
11
12
1234
1245
124567
126786
145769

such that:

a1??? a2
1???? 1
1???? 2
12??? 23
12??? 34
124?? 567
126???787
145???769 ?
I tried logical commands with substr() did not work out.

Hi:

Here's one take:

shalve <- function(x) {
   nc <- sapply(x, nchar)
   ns <- nc %/% 2
   cbind(a1 = substring(x, 1, ns),
        a2 = substring(x, ns + 1, nc))
  }
> shalve(a)
     a1    a2
[1,] "1"   "1"
[2,] "1"   "2"
[3,] "12"  "34"
[4,] "12"  "45"
[5,] "124" "567"
[6,] "126" "786"
[7,] "145" "769"

HTH,
Dennis

On Wed, Jul 6, 2011 at 8:41 PM, Peter Maclean <pmaclean2011 at yahoo.com>
wrote:
> How to substring the following vector (in data frame b)
>>b
> a
> 11
> 12
> 1234
> 1245
> 124567
> 126786
> 145769
>
> such that:
>
> a1??? a2
> 1???? 1
> 1???? 2
> 12??? 23
> 12??? 34
> 124?? 567
> 126???787
> 145???769
> I tried logical commands with substr() did not work out.
>
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