input
one two three four
0 0 0 10424
0 102 0 15091
1 298 34 11111
0 10 0 1287
scripts
awk 'NR>1{print ($1/$2) / ($3/$4)}'
awk 'NR>1{ if ($1 ||$3 ||$2|| $4 == 0) print 0; else print (($1/$2)/($3/$4))}'
error
awk: division by zero
input record number 1, file rm
source line number 1
awk '!$1 || !$2 || !$3 || !$4 {print "0";next}{print (($1/$2)/($3/$4))}' file
I still get the error:
$ awk '!$1 || !$2 || !$3 || !$4 {print "0";next}{print (($1/$2)/($3/$4))}' infile
awk: (FILENAME=infile FNR=1) fatal: division by zero attempted
Try this:
$ awk 'NR>1{print (!$1 || !$2 || !$3 || !$4)? "0":($1/$2)/($3/$4)}' infile
0
0
1.09662
0
While both Franklin52's and rdcwayx's solutions work for me, neither should, according to POSIX.
If i'm not mistaken, the portable way to write
!$1 || !$2 || !$3 || !$4
is
!($1+0) || !($2+0) || !($3+0) || !($4+0)
to explicitly demand that each field variable be treated as a number.
The standard says that in a boolean context (such as the logical not), if the type is a number, 0 is false and all others are true; if the type is a string, the null string is false and all others are true. There is no conversion of type (as there is when comparing, in which case a 'numeric string' is coerced to a number if the other value is a number). So when a field is "0", that's a true value in a boolean context since it's a non-empty string.
I think I'd just go with an explicit comparison to zero, $i == 0, since it's both clear and portable (the hardcoded number 0 ensures that the field value is treated as a number).
For more detailed info, refer to the 'Expressions in awk' section @ awk
Wow, that's a lot of typing for a little division. 
Regards,
Alister
Ok, for Franklin52's command, if I remove the first line from input file, it is fine.
The reason why the problem is fixed in my code, because I add NR>1 , otherwise, same error I will get.
yes, you can.
awk 'NR>1{print ($1=="0" || $2=="0" || $3=="0" || $4=="0")? "0":($1/$2)/($3/$4)}' infile
I mean instead of typing
($1=="0" || $2=="0" || $3=="0" || $4=="0")
is is there any short way of doing it ? Because I have around 300 columns to specify as 0. Thanx
awk 'NR>1{print $2*$3*$4?($1/$2)/($3/$4):0}' infile
