I have an array trf. Would like to compute the sum of the second element in each array entry.
Example of array contents
trf=( "2 13 144" "3 21 256" "5 34 389" )
Here is the current implementation, but I do not find it robust enough. For instance, it fails with arbitrary number of elements (but considered constant from one array element to another) in each array entry.
cnt=0
m=${#trf[@]}
while (( cnt < m )); do
while read -r one two three
do
sum+="$two"+
done <<< $(echo ${array[$count]})
let count=$count+1
done
sum+=0
result=`echo "$sum" | /usr/bin/bc -l`
You're making it way too complicated. Something like
#!/usr/bin/env bash
trf=( "2 13 144" "3 21 256" "5 34 389" )
declare -i sum=0 # Integer attribute; arithmetic evaluation happens when assigned
for (( n = 0; n < ${#trf[@]}; n++)); do
read -r _ val _ <<<"${trf[n]}"
sum+=$val
done
printf "%d\n" "$sum"
in pure bash, or just use awk (This is handy if you have floating point numbers in your real data):
printf "%s\n" "${trf[@]}" | awk '{ sum += $2 } END { print sum }'