Translating a lookup-dictionary to bash: Much simpler than I thought

I wanted to name Transcom Regions [1] in my plots by passing their names to the command-line tool, but I only had their region-number and a lookup dictionary in Python. To avoid tampering with the tool, I needed to translate the dictionary to a bash function, and thanks to the case statement [2] it was much simpler than I had expected.

This is the original dictionary:

#: Names of transcom regions
transcomregionnames = {
    1: "NAM Boreal",
    2: "NAM Temperate",
    3: "South American tropical",
    # and so forth
}

This is how lookup works in Python:

region = 2
name = transcomregionnames[2]

The solution in bash is a simple mechanic translation:

function regionname () {
    number="$1"
    case $number in
        1) echo "NAM Boreal";;
        2) echo "NAM Temperate";;
        3) echo "South American tropical";;
        # and so forth
    esac
}

And the lookup is easier than anything I hoped for:

region=2
name=$(regionname $region)

This is how it looks in my actual code:

for region in {1..22} ; do ./plotstation.py -c /home/arne/sun-work/ct-tccon/ct-tccon-2015-5x7-use-obspack-no-tccon-nc/ -C "GA: in-situ ground and aircraft"  -c /home/arne/sun-work/ct-tccon/ct-tccon-2015-5x7-use-obspack-use-tccon-noassimeu/ -C "TneGA: non-European TCCON and GA" -c /home/arne/sun-work/ct-tccon/ct-tccon-2015-5x7-use-obspack-no-tccon-no-aircraft-doesitbreaktoo/ -C "G: in-situ ground"  --regionfluxtimeseries $region --toaverage 5 --exclude-validation  --colorscheme paulforabp --linewidth 4 --font-size 36 --start 2009-12-03 --stop 2012-12-02  --title "Effect of assimilating non-EU TCCON, $(regionname ${region})"  -o ~/flux-GA-vs-TneGA-vs-G-region-${region}.pdf; done

For your convenience, here’s my entire transcom naming function:

function regionname () {
    number="$1"
    case $number in
        1) echo "NAM Boreal" ;;
        2) echo "NAM Temperate";;
        3) echo "South American tropical";;
        4) echo "South American temperate";;
        5) echo "Northern Africa";;
        6) echo "Southern Africa";;
        7) echo "Eurasian Boreal";;
        8) echo "Eurasian Temperate";;
        9) echo "Tropical Asia";;
        10) echo "Australia";;
        11) echo "Europe";;
        12) echo "North Pacific Temperate";;
        13) echo "West Pacific Tropics";;
        14) echo "East Pacific Tropics";;
        15) echo "South Pacific Temperate";;
        16) echo "Northern Ocean";;
        17) echo "North Atlantic Temperate";;
        18) echo "Atlantic Tropics";;
        19) echo "South Atlantic Temperate";;
        20) echo "Southern Ocean";;
        21) echo "Indian Tropical";;
        22) echo "South Indian Temperate";;
    esac
}

Happy Hacking!