linux + ksh + Round down or Round up - float numbers

问题:

in my ksh script I need to calculate only integer numbers

Sometimes I get float numbers such as 3.49 or 4.8...etc

so I need to translate the float numbers to integer’s numbers according to the following rules (examples)

3.49     will be 3 2.9      will be 3 4.1      will be 4 23.51    will be 24 982.4999 will be 982  10.5     will be 11  ( this example if float is .5 then it will roundup ) 

Please advice how to do this in ksh or awk or perl

Or

any other language that can be run in my ksh script

回答1:

After a brief google session, I found that printf seems to be able to do the job, at least in bash (couldn't find an online interpreter that does ksh).

printf "%0.f\n" 4.51 5 printf "%0.f\n" 4.49 4 

Code at: http://ideone.com/nEFYF

Note: perl might be overkill, like Marius says, but here's a perl way:

The perl module Math::Round seems to handle the job.

One-liner:

perl -MMath::Round -we 'print round $ARGV[0]' 12.49 

Script:

use v5.10; use Math::Round; my @list = (3.49, 2.9, 4.1, 23.51, 982.4999);  say round $_ for @list; 

Script output:

3 3 4 24 982 

回答2:

In awk you can use the int() function to truncate the values of a floating point number to make it integer.

[jaypal:~/Temp] cat f 3.49     will be 3 2.9      will be 3 4.1      will be 4 23.51    will be 24 982.4999 will be 982  [jaypal:~/Temp] awk '{x=int($1); print $0,x}' f 3.49     will be 3 3 2.9      will be 3 2 4.1      will be 4 4 23.51    will be 24 23 982.4999 will be 982 982 

To Round off you can do something like this -

[jaypal:~/Temp] awk '{x=$1+0.5; y=int(x); print $0,y}' f 3.49     will be 3 3 2.9      will be 3 3 4.1      will be 4 4 23.51    will be 24 24 982.4999 will be 982 982 

Note: I am not sure how you would like to handle numbers like 2.5. The above method will return 3 for 2.5.

回答3:

Versions of ksh that do non-integer math probably have floor(), trunc(), and round() functions. Can't check 'em all, but at least on my Mac (Lion), I get this:

$ y=3.49 $ print $(( round(y) )) 3 $ y=3.51 $ print $(( round(y) )) 4 $ (( p = round(y) )) $ print $p 4 $ 

回答4:

In perl, my $i = int($f+0.5);. Should be similar in the other, assuming they have a convert to integer or floor function. Or, if like in javascript, they have a Math.round function which could be used directly.

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