Monday, January 5, 2009
Round functionality with awk - bash shell
As there is no standard "round" function available in awk, some of the ways to round float values to the rounded integer.
$ echo "23.54" | awk '{printf("%d\n",$1 + 0.5)}'
24
$ echo "23.49" | awk '{printf("%d\n",$1 + 0.5)}'
23
Lets make this a function named round.
$ echo "23.54" | awk '
function round(A) {
return int( A + 0.5 )
}
{
printf("%d\n",round($1));
}'
24
Another way:
$ echo "23.54" | awk '{printf("%d\n",$0+=$0<0?-0.5:0.5)}'
24
Related post:
round float values using sprintf in awk
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8 comments:
Why bother with awk? 'printf' is a bash builtin:
$ printf "%.0f\n" "23.54"
24
$ printf "%.0f\n" "23.44"
23
@JP, thanks. Its helpful.
The reason I tried with awk (using printf though), as my original intention was to round only one field(column) out of several columns of a delimited file(as shown in the related post link in the post). Thanks for posting.
// Jadu
Note that this solution does not work with negative numbers. Use JP's suggestion in awk to cover both positive and negative numbers.
@stinkinrich88, thanks for pointing this.
With a little added coding you can specify the number of decimal places, as well as deal with negative numbers:
function round(num,places, sign) {
# Rounds to /places/ decimal points - if /places/ not supplied it is
# treated as 1, also can supply negative /places/
places=10^places
sign=1
if (num < 0) {sign = -1; num = -num;}
return sign * int(num*places + .5)/places
}
Hi,
I am having some trouble on rounding to nearest minute.
I have a file with different values. One of the columns is time.
Ex.:
0:0:17
0:1:18
0:2:19
0:19:33
0:26:49
What I need to do is rounding up and down depends on the number of seconds (if up to 30 then rounding down, if more then 30 rounding up). So 0:0:17 will become 00:00 and 0:26:49 will become 00:27.
I mention that I am on a bash shell.
Thank you,
R.
@Raluca Brez , thanks for the question. I can quickly think of this:
$ cat file.txt
0:0:17
0:1:18
0:2:19
0:19:33
0:26:49
$ awk -F ":" 'BEGIN {OFS=":"}{if($NF>30) {$2+=1}{print $1,$2}}' file.txt
0:0
0:1
0:2
0:20
0:27
Hope this helps. Thanks.
Hi, thank you for you quick response, Yes, that was very useful. Thanks again.
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