awk calculate average or zero

Question

I am calculating the average for a bunch of numbers in a bunch of text files like this:

grep \'^num\' file.$i | awk \'{ sum += $2 } END { print sum / NR }\'
         


        

Answer 1

Use awk's ternary operator, i.e. m ? m : n which means, if m has a value '?', use it, else ':' use this other value. Both n and m can be strings, numbers, or expressions that produce a value.

grep '^num' file.$i | awk '{ sum += $2 } END { print sum ? sum / NR : 0.0 }'