使用awk计算数字的平均值

Question

I have a file named test.txt with the following:

10
200
3000
=======
4
5
=======

I need to write an awk script to take the text in this file as input into the awk script and output:

10
200
3000

Average 1070.00

4
5

Average 4.50

I wrote my script like this:

{while($1!~"=======") s+=$1;}
{print "Average ", s}

Every time I run this code, I use:

awk -f awrp4 test.txt

But it crashes. I don't know what I'm doing wrong. I'm a beginner and trying to learn about the awk function so I apologize if this seems rather simple. Any help is welcome.

Answer 1

Using GNU awk, you can write:

gawk '
    BEGIN {FS = "\n"; RS = "\n=+\n"}
    NF > 0 {
        sum = 0
        for (i=1; i<=NF; i++) {
            print $i
            sum += $i
        }
        printf "Average %.2f\n", sum/NF
    }
' file

Answer 2

Certainly nothing wrong with Glenn's solution, but it might be a bit advanced for you. Maybe this is better suited:

{
if ($1 == "=======") {
    print "\nAverage " s/i "\n";
    s=0;
    i=0;
} else {
    print $1;
    s += $1;
    i += 1;
}
}

As I mentioned in the comments, the nature of awk is to loop through every line of a text file. Unless you're doing some post-processing or working with arrays, a while loop probably isn't of much use.

Answer 3

awk '$1~/^[[:digit:]]/ {i++; sum+=$1; print $1} $1!~/[[:digit:]]/ {print "Average", sum/i; sum=0;i=0}' file

• The first part checks if the first character from column 1 is a digit, if so then increment the counter 'i' and add that record(number) to sum.
• The second part is to skip any record that does not start with a digit, and then you print the average by dividing sum/i, finally reset counter and sum to 0.