Split strings into columns in R where each string has a potentially different number of column entries

Question

I\'ve got a data frame that\'s got the following form

pages                         count
[page 1, page 2, page 3]      23
[page 2, page 4]              4
[p         


        

Answer 1

read.table with fill=TRUE can fill them in. The names(DF2)<- line could be omitted if nice column names are not important. No packages are used.

# test data

Lines <- "pages                         count
[page 1, page 2, page 3]      23
[page 2, page 4]              4
[page 1, page 3, page 4]      12"

# code - replace text=Lines with something like "myfile.dat"

DF <- read.table(text = Lines, skip = 1, sep = "]", as.is = TRUE)
DF2 <- read.table(text = DF[[1]], sep = ",", fill = TRUE, as.is = TRUE)
names(DF2) <- paste0(read.table(text = Lines, nrow = 1, as.is = TRUE)[[1]], seq_along(DF2))
DF2$count <- DF[[2]]
DF2[[1]] <- sub(".", "", DF2[[1]]) # remove [

which gives this:

> DF2
  pages1  pages2  pages3 count
1 page 1  page 2  page 3    23
2 page 2  page 4             4
3 page 1  page 3  page 4    12

Note: This gives columns headings of page1, page2, etc. If it were important to have precisely the column headings shown in the question then replace that line with this which uses those headings if there are less than 20 page columns.

 ord <- c('First', 'Second', 'Third', 'Fourth', 'Fifth', 'Sixth', 'Seventh',
 'Eighth', 'Ninth', 'Tenth', 'Eleventh', 'Twelfth', 'Thirteenth',
 'Fourteenth', 'Fiftheenth', 'Sixteenth', 'Seventeenth', 'Eighteenth', 
 'Nineteenth')
ix <- seq_along(DF2)
names(DF2) <- if (ncol(DF2) < 20) paste(ord[ix], "Page") else paste("Page", ix)