topic Re: Strange output format using sum in Operating System - HP-UX

Strange output format using sum

Wagner Villela — Fri, 16 Mar 2012 16:22:21 GMT

Dear friends,

I'm doing a column sum using cat+awk+sum (like below) and the final result comes in a strange format.

cat lixo_avb | awk '{ sum+=$2} END {print sum}'

1.42881e+06

I think it's have some simple solution, but i try some google searches and i can't find any explanation.

Some help?

Thanks

Re: Strange output format using sum

Matti_Kurkela — Fri, 16 Mar 2012 16:45:08 GMT

That's a variant of scientific notation that is actually quite common with computers, called "E notation." It's useful for compact representation of very large or very small numbers.

1.42881e+06 means:

1.42881 * (10^6) = 1 428 810

http://en.wikipedia.org/wiki/Scientific_notation

Re: Strange output format using sum

Patrick Wallek — Fri, 16 Mar 2012 16:47:22 GMT

1.42881e+06 means 1.42881 x 10^6 (10 to the 6th power) -- This is standard engineering format and essentially means that you need to move the decimal 6 places to the right.

So 1.42881e+06 = 1,428,810

Re: Strange output format using sum

Wagner Villela — Fri, 16 Mar 2012 17:16:26 GMT

Thanks, dudes.

Someone knows any way to force results in a "normal" output.

Change some parameter, etc...

edit to say...

# echo '1.42881e+06' | awk '{printf "%.0f\n", $0}'

# 1428810

Well, works fine, but i like to get this result direct from first calc.

Re: Strange output format using awk (scientific notation)

Dennis Handly — Fri, 16 Mar 2012 19:10:10 GMT

>but I like to get this result direct from first calc.

Searching the forum should show you many examples. From awk(1):

awk '

BEGIN { OFMT = "%.0f" }

{ sum+=$2}

END {print sum}' lixo_avb

This also gets rid of the evil cat. :-)

Re: Strange output format using sum

Matti_Kurkela — Fri, 16 Mar 2012 18:54:48 GMT

The awk function '{printf "%.0f\n", $0}' does not explicitly mean "convert a number from scientific format to regular one", but simply "output this number in this format". Since awk uses standard C library routines, it understands scientific notation automatically. For awk and any other program that uses the standard scanf functions, scientific notation is freely interchangeable with ordinary number notation, unless the programmer has taken deliberate steps to reject input that uses scientific notation.

So you'll just have to add the output format specification "%.0f" to your original calculation. To do that, you'll need to switch "print" to "printf", and since printf does not output a newline character unless you explicitly request for it (with \n), you'll have to add that, too.

cat lixo_avb | awk '{ sum+=$2} END {printf "%.0f\n",sum}'

Re: Strange output format using sum

Wagner Villela — Fri, 16 Mar 2012 18:58:43 GMT

You guys rock!

Thanks.