split strings on first and last commas

Question

I would like to split strings on the first and last comma. Each string has at least two commas. Below is an example data set and the desired result.

A similar ques

Answer 1

Here is a relatively simple approach. In the first line we use sub to replace the first and last commas with semicolons producing s. Then we read s using sep=";" and finally cbind the rest of my.data to it:

s <- sub(",(.*),", ";\\1;", my.data[[1]])
DF <- read.table(text=s, sep =";", col.names=paste0("mystring",1:3), as.is=TRUE)
cbind(DF, my.data[-1])

giving:

  mystring1 mystring2 mystring3 some.data
1       123  34,56,78        90        10
2        87     65,43        21        20
3        a4        b6     c8888        30
4        11      bbbb     ccccc        40
5        uu     vv,ww        xx        50
6         j k,l,m,n,o         p        60