larger.md

Snippets larger than just a few lines

1 - 24th letter of (ascii) alphabet

This one works also in dash(1). bash/zsh could just index the string...

0-23 -indexed. I have one usecase where I split day in a 2 letter string, 1st per hour, 2nd per 2.5 minutes (150 seconds).

Somewhat easy to extend...

nth_lc_letter ()
{
    local l u; l=$1 # IIRC local did not work in ksh...
    test $l -ge 12 && u=mnopqrstuvwx l=$((l - 12)) || u=abcdefghijkl
    test $l -ge 6 && u=${u#??????} l=$((l - 6))
    test $l -ge 3 && u=${u#???} l=$((l - 3))
    test $l -ge 2 && u=${u#??} l=$((l - 2))
    test $l -ge 1 && u=${u#?} l=$((l - 1))
    l=${u#?}
    printf '%2d %s\n' $1 ${u%$l}
}
# test code
x=0; while test $x -le 23; do nth_lc_letter $x; x=$((x + 1)); done

Version w/o local vars, and one var (l) where the result is

nth_lc_letter ()
{
    test $1 -ge 12 && { l=mnopqrstuvwx; set -- $(($1 - 12)); } ||
                        l=abcdefghijkl
    test $1 -ge 6 && { l=${l#??????}; set -- $(($1 - 6)); }
    test $1 -ge 3 && { l=${l#???}; set -- $(($1 - 3)); }
    test $1 -ge 2 && { l=${l#??}; set -- $(($1 - 2)); }
    test $1 -ge 1 && { l=${l#?}; set -- $(($1 - 1)); }
    set -- ${l#?}
    l=${l%$1}
}
# test code
x=0
while test $x -le 23; do nth_lc_letter $x; echo $x $l; x=$((x + 1)); done