使用awk计算平均成绩

Question

I have a file like this:

id1 name1 grade1 grade2 grade3....gradeN
id2 name2 grade1 grade2 grade3....gradeN
etc

and I want to print the id, name and average of grades of each row using awk. any idea? the output should be like:

id1 name1 avg_of_grades
id2 name2 avg_of_grades

Answer 1

Using awk :

awk '{sum=0;for(i=3;i<=NF;i++) sum+=$i; print $1, $2, (NF>2?sum/(NF-2):0)}' file

Iterate from third column to end of line and capture the total in a variable called sum . Once that is done, just print column 1, 2 and the average. Since sum will contain rolling total, we set it to 0 at the start of our script to initialize it for each line.

Note for average, I used NF variable which contains the total number of columns for each line. We subtract 2 to get correct total (we start capture from third column).

Also, I have added a check for division by zero in cases you just have two columns.