How can I make awk not use scientific notation when printing small values?

Question

In the following awk command

 awk '{sum+=$1; ++n} END {avg=sum/n; print "Avg monitoring time = "avg}' file.txt

what should I change to remove scientific notation output (very small values displayed as 1.5e-05) ?

I was not able to succeed with the OMFT variable.

score 64 · Accepted Answer · answered Oct 03 '12 at 18:01

64

You should use the printf AWK statement. That way you can specify padding, precision, etc. In your case, the %f control letter seems the more appropriate.

answered Oct 03 '12 at 18:01

C2H5OH

5,452
2
27
39

34

For those who don't often use awk and forget the syntax, here is an example: `echo ""|awk '{printf "%.2f", 1566666666/50}'` – Aaron R. Jul 02 '14 at 21:38
1

Also note that even if you're summing up integers, [you probably want to use `%f`](http://stackoverflow.com/a/25245025/120999). – Xiong Chiamiov Oct 11 '16 at 00:46
1

@AaronR. If you don't need `awk` to take any input, you could do `awk 'BEGIN{printf "%.2f", 1566666666/50}'` to use your example. The default selector is `$0`, which is the standard input, & waits for a newline in standard input before running, but `BEGIN` doesn't wait for anything on standard input. Also, to just output a newline, you can just do `echo`, you don't need `echo ""`. – JustinCB Jul 13 '18 at 20:12
1

You can use eg. `awk '{print sprintf("%.10f", $1/$2), $2}'` – macieksk Jun 10 '20 at 13:40

score 16 · Answer 2 · edited Nov 19 '21 at 17:31

16

I was not able to succeed with the OMFT variable.

It is actually OFMT (outputformat), so for example:

awk 'BEGIN{OFMT="%f";print 0.000015}'

will output:

0.000015

as opposed to:

awk 'BEGIN{print 0.000015}'

which output:

1.5e-05

GNU AWK manual says that if you want to be POSIX-compliant it should be floating-point conversion specification.

edited Nov 19 '21 at 17:31

toraritte

6,300
3
46
67

answered Dec 01 '20 at 12:04

Daweo

31,313
3
12
25

score 5 · Answer 3 · answered Feb 09 '21 at 01:48

Setting -v OFMT='%f' (without having to embed it into my awk statement) worked for me in the case where all I wanted from awk was to sum columns of arbitrary floating point numbers.

As the OP found, awk produces exponential notation with very small numbers,

$ some_accounting_widget | awk '{sum+=$0} END{print sum+0}'
8.992e-07  # Not useful to me

Setting OFMT for fixed that, but also rounded too aggressively,

$ some_accounting_widget | awk -v OFMT='%f' '{sum+=$0} END{print sum+0}'
0.000001   # Oops. Rounded off too much. %f rounds to 6 decimal places by default.

Specifying the number of decimal places got me what I needed,

$ some_accounting_widget | awk -v OFMT='%.10f' '{sum+=$0} END{print sum+0}'
0.0000008992    # Perfect.

How can I make awk not use scientific notation when printing small values?

3 Answers3

Linked

Related