read/write file

gistfile1.groovy

int i = 0;
File file = new File("out2.csv")
file << "Id,Action\n"

new File('out.csv').eachLine { line ->
  if(i > 0) {
    file.append i
  	file.append ','
  	file.append Double.valueOf(line) > 0.6 ? 1 : 0;
  	file.append '\n'
  }
  i++
}