CODEWITHSUNDEEP
bashshell
sovon
sovon

Reputation: 907

floating point number comparison in bash script

I tried to compare floating point number by -gt but it says that point expecting integer value. That means it can not handle floating point number . Then i tried the following code 

chi_square=4
if [ "$chi_square>3.84" | bc ]
then
echo yes
else
echo no
fi

But the output is wrong with error . Here is the out put-

line 3: [: missing `]'
File ] is unavailable.
no

Here the no is echoed but it should be yes. I think that's because of the error it's showing. can anybody help me.

Upvotes: 1

Views: 120

Answers (2)

Ed Morton
Ed Morton

Reputation: 203985

Keep it simple, just use awk:

$ awk -v chi_square=4 'BEGIN{print (chi_square > 3.84 ? "yes" : "no")}'
yes

$ awk -v chi_square=3 'BEGIN{print (chi_square > 3.84 ? "yes" : "no")}'
no

or if you prefer avoiding ternary expressions for some reason (and also showing how to use a value stored in a shell variable):

$ chi_square=4
$ awk -v chi_square="$chi_square" 'BEGIN{
    if (chi_square > 3.84) {
        print "yes"
    }
    else {
        print "no"
    }
}'
yes

or:

$ echo "$chi_square" |
awk '{
    if ($0 > 3.84) {
        print "yes"
    }
    else {
        print "no"
    }
}'
yes

or to bring it full circle:

$ echo "$chi_square" | awk '{print ($0 > 3.84 ? "yes" : "no")}'
yes

Upvotes: 0

anubhava
anubhava

Reputation: 785491

If you want to use bc use it like this:

if [[ $(bc -l <<< "$chi_square>3.84") -eq 1 ]]; then
   echo 'yes'
else
   echo 'no'
fi

Upvotes: 2

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