Split a string column into several dummy variables

Question

As a relatively inexperienced user of the data.table package in R, I\'ve been trying to process one text column into a large number of indicator columns (dummy variables), w

Answer 1

Here's a somewhat newer approach, using cSplit_e() from the splitstackshape package.

library(splitstackshape)
cSplit_e(dt, split.col = "String", sep = "$", type = "character", 
         mode = "binary", fixed = TRUE, fill = 0)
#  ID String String_a String_b String_c
#1  1    a$b        1        1        0
#2  2    b$c        0        1        1
#3  3      c        0        0        1