Arrays and Tables

Parallel Arrays

Count Matching Rows

Two arrays can model a tiny table when each position belongs to the same row. A loop can scan the rows and count matches.

Program

Play the script to choose a status filter and see how many rows match it.

parallel_array_filter.sh 
#!/usr/bin/env bash

ids=("A1" "B2" "C3")
states=("ready" "blocked" "ready")
status_filter=
matches=0
for i in "${!ids[@]}"; do
    if [[ "${states[$i]}" == "$status_filter" ]]; then
        matches=$((matches + 1))
    fi
done
echo "$status_filter:$matches"

#!/usr/bin/env bash

ids=("A1" "B2" "C3")
states=("ready" "blocked" "ready")
status_filter=
matches=0
for i in "${!ids[@]}"; do
    if [[ "${states[$i]}" == "$status_filter" ]]; then
        matches=$((matches + 1))
    fi
done
echo "$status_filter:$matches"
parallel arrays Parallel arrays use the same index to connect fields from the same row.
array indexes `${!ids[@]}` expands to the indexes present in the array.
row filter The loop compares each row's status with the selected filter.