Question

If I have a variable holding a string representation of a comparative operator such as:

> comparison <- "=="

how can I interpolate this string version of the binary operator between its operands? E.g.

> 2 <insert comparison> 2
TRUE

NB. I do not want to use mapply(get(comparison),2,2 since I intend to put 2 <insert comparison> 2 as an argument to which.

Answer 1

I don’t quite understand why you don’t want to use mapply, but do.call is probably better anyway.

comparison <- "=="
do.call(comparison, list(2,2))

which( do.call(comparison, list(2,0:4)) )