Now I am wondering if there is a more efficient way to write the parameters of this code?
Yes. You get a distance reading. Then you assign that to proxcont. Then, you get another reading and print the value.
Just assign the value from the first call to sonar.ping_cm() to proxcont, and then print proxcont. You never use distance anywhere else, so you don't need it.
You never use the readings array, either, so kiss it goodbye, too.