Awk product of nth field

[madhavb]

How do I do the product of nth filed just like sum. For sum I know like
awk '{ sum += $12 } END {printf "%.2f\n", sum}'
works as initial sum = 0.

But for product how do initialize the variable to 1?

[drl]

Hi.

Concisely:

awk 'BEGIN{p=1}{p *= $1}END{print "p for",NR,"lines = ",p}' input_file

so for a file 1,2,3 on separate lines one obtains, say for the data on file z7

p for 3 lines =  6

The man page on awk can seem long, but is very useful for factual questions.

Best wishes ... cheers, drl