calculate and print the average value of strings in a column

Question

I got a .txt file with 2 columns of values. They are 2D coordinates, so the first column represent the x value and the second one is the z value. Unfortunately there are som

Answer 1

This is one way with awk:

$ awk '{a[$1]+=$2; ++b[$1]} END {for (i in a) print i, a[i]/b[i]}' file
435.212 108.899
435.25 108.9
435.238 108.9
435.262 108.9
435.275 108.9

Explanation

{a[$1]+=$2; ++b[$1]}

• Store the z values (2nd column) in the array a.
• Store the amount of elements for each x value (1st column) in the array b.

END {for (i in a) print i, a[i]/b[i]}'

• Print the result looping through the values stored in the array.

To have another number format (4 float values for example) you can also use:

printf "%d %.4f\n", i, a[i]/b[i]