how to create a quoted expression from strings

Question

Given a vector of strings, I would like to create an expression without the quotation marks.

# eg, I would like to go from 
c(\"string1\", \"string2\")

# to...         


        

Answer 1

I tend to use as.quoted from the plyr package

 outputString <- sprintf('list(%s)', paste(input, collapse = ', ')) 


 library(plyr)
  output <- as.quoted(outputString)[[1]]

  mydt[, eval(output)]
   string1 string2
1:       A       a
2:       B       b
3:       C       c

However if it is simply column selection, you can pass the string and use .. (which, like in the Unix terminal, means to "look up one level")

mydt[ , ..input]
   string1 string2
1:       A       a
2:       B       b
3:       C       c