LinuxQuestions.org - bc,getopt and arrays in bash

- Linux - Newbie (http://www.linuxquestions.org/questions/linux-newbie-8/)

- - bc,getopt and arrays in bash (http://www.linuxquestions.org/questions/linux-newbie-8/bc-getopt-and-arrays-in-bash-915381/)

congos

11-24-2011 03:17 PM

bc,getopt and arrays in bash

trying to sum elements in an array using bc and getopt,i have a file with names and thier vaules if the names appears 3 times i should multiply its value with 3 then find the sum of all the elements together

cat foo.txt

max 2.3
henry 3
fransis 4.5
max 2.3
henry 3
max 2.3

it should show on the terminal
max 6.9
henry 6
fransis 4.5

and so on
im trying to avoid awk

David the H.

11-24-2011 03:53 PM

Why would you want to avoid awk? This is a perfect application for it:

Code:

awk '{ array[$1] += $2 } END{ for ( i in array ) { print i , array[i] } }' file

I also don't understand your reference to getopt. What does that have to do with it?

Anyway, using the same basic logic as the above awk command, and bash v4's associative arrays:

Code:

declare -A array



while read name value; do



     array[$name]=$( echo "${array[$name]:-0} + $value" | bc )



done < file



for name in "${!array[@]}"; do



     echo "$name ${array[$name]}"



done

jhwilliams

11-24-2011 03:53 PM

This Bash 4.0+ script using an associative array seems to work. Could probably be simpler.

Code:

#!/bin/bash



declare -A map



while read line; do

    key=${line%% *}

    value=${line##* }

    [ -z "${map[$key]}" ] && map[$key]=0

    map[$key]=$(bc <<< "${map[$key]} + $value")

done < $@



for person in ${!map[*]}; do

    echo -e $person\: ${map[$person]}

done

EDIT: Oops, yea, David's is cleaner.

All times are GMT -5. The time now is 05:24 PM.