[R] Pulling strings from a Flat file

[David Winsemius]

On Apr 5, 2011, at 7:48 PM, Kalicin, Sarah wrote:

> Hi,
>
> I have a flat file that contains a bunch of strings that look like  
> this. The file was originally in Unix and brought over into Windows:
>
> E123456E234567E345678E456789E567891E678910E. . . .
> Basically the string starts with E and is followed with 6 numbers.  
> One string=E123456, length=7 characters. This file contains 10,000's  
> of these strings. I want to separate them into one vector the length  
> of the number of strings in the flat file, where each string is it's  
> on unique value.
>
> cc<-c(7,7,7,7,7,7,7)
>> aa<- file("Master","r", raw=TRUE)
>> readChar(aa, cc, useBytes = FALSE)
> [1] "E123456"  "\nE23456" "7\nE3456" "78\nE456" "789\nE56"  
> "7891\nE6" "78910\nE"
>> close(aa)
>> unlink("Master")

 > txt <- "E123456E234567E345678E456789E567891E678910E"
# You could use readLines to bring in from the file
# and assign to a character vector for work in R.

 > gsub("(E[[:digit:]]{6})", "\\1\n", txt)
[1] "E123456\nE234567\nE345678\nE456789\nE567891\nE678910\nE"
# Seems to be "working" properly

 > ?scan

 > scan(textConnection(gsub("(E[[:digit:]]{6})", "\\1\n", txt)),  
what="character")
Read 7 items
[1] "E123456" "E234567" "E345678" "E456789" "E567891" "E678910" "E"

You might be able to use read.table or variants.

>
> The biggest issue is I am getting \n added into the string, which I  
> am not sure where it is coming from, and splices the strings. Any  
> suggestions on getting rid of the /n and create an infinite sequence  
> of 7's for the string length for the cc vector? Is there a better  
> way to do this?
>
> Sarah
>

David Winsemius, MD
West Hartford, CT