R use variable within regex

Question

Okay - maybe this is a better example. I am looking for guidance/references on how to reference a variable within a regex - not how to build a regex for this data.

Answer 1

You'll need to escape various characters to use variables in regex, but why not do the simpler thing?

sub('(.*)ICA.*', '\\1', d1)
#[1] "CCA: 135 cm/sec " "CCA: 150 cm/sec "
sub('.*(ICA.*)', '\\1', d1)
#[1] "ICA: 50 cm/sec" "ICA: 75 cm/sec"