separate elements of array in bash

Question

I have an array, on the attached screen.

I need to get all third components from this array.

Example (my existing array):

array1 = 
 ["SRV WW ZSTG HSM BlackDuck RW", "SRV WW ZSDB M204 BlackDuck RW", etc] 

The result should be:

array2 = ["HSM", "M204"]

• I need to delete all empty elements from array

My code to work with it right now:

FILE="$1"

index=0
while read name; do
    get_group_names_from_file[$index]="$name"
    index=$(($index+1))
done < "${FILE}"

get_group_names_from_file=("${get_group_names_from_file[@]:3}")

for ((a=0; a < ${#get_group_names_from_file[*]}; a++))
do
    echo "${get_group_names_from_file[$a]}"
done

Answer 1

If you only need the third column you can use the cut command (see man page):

FILE="$1"

for value in `cat $FILE | cut -d ' ' -f 3`
do
    echo "3rd column is $value"
done

Answer 2

I've set ARRAY1 like this (there's no need for a , to seperate values in an array):

ARRAY1=("SRV WW ZSTG HSM BlackDuck RW" "SRV WW ZSDB M204 BlackDuck RW")

and extracted the third component of the array-values this way:

for (( i=0 ; i<$(echo ${#ARRAY1[*]}) ; i++ )) ; do ARRAY2+=($(echo ${ARRAY1[$i]} | cut -d ' ' -f3)); done

(If you want to have the 4th component, use cut -d ' ' -f4 instead)

Checking values of ARRAY2 via printf '%s\n' "${ARRAY2[@]}"

---

~$ ARRAY1=("SRV WW ZSTG HSM BlackDuck RW" "SRV WW ZSDB M204 BlackDuck RW")
~$ ARRAY2=() ; for (( i=0 ; i<$(echo ${#ARRAY1[*]}) ; i++ )) ; do ARRAY2+=($(echo ${ARRAY1[$i]} | cut -d ' ' -f3)); done
~$ printf '%s\n' "${ARRAY2[@]}"
~$ ZSTG
~$ ZSDB

Answer 3

This feels like an XY problem to me.
You talk about arrays, but you read a file. I'll put the data into arrays, in case that's what you needed...

If you need arrays, read it as an array.

$: cat xy.dat # used the two you had in your array that I could copy/paste
SRV WW ZSTG HSM BlackDuck RW
SRV WW ZSDB M204 BlackDuck RW

$: cat xy
#! /bin/env bash

declare -a array1=() array2=()
while read -ra row
do array1+=( "${row[*]}" ) # NOTE: using * makes one string of the row; @ would separate them
   [[ -n "${row[3]}" ]] && array2+=( "${row[3]}" )
done < "$1" # don't use capital FILE.

declare -p array1 array2 # show the contents

$: xy xy.dat
declare -a array1=([0]="SRV WW ZSTG HSM BlackDuck RW" [1]="SRV WW ZSDB M204 BlackDuck RW")
declare -a array2=([0]="HSM" [1]="M204")

If you don't particularly need arrays, or only need the second one, then simplify.

$: cat xy
#! /bin/env bash
while read -r one two three four five six
do [[ -n "$four" ]] && array2+=( "$four" )
done < "$1"
declare -p array2

$: xy xy.dat
declare -a array2=([0]="HSM" [1]="M204")

If you don't particularly need array2 either, just do whatever parsing you needed as you read through.

Good luck.