How to get bash indexes of parameters array?

Question

I want indexes of parameters,

and can get it by dummy var:

dummy=( $@ )
echo ${!dummy[@]}

but is there straight way to get them, something like

$!@ ... not working
$!* ... not working

... or something like that?

NOTE: original function that i want to have without arr var is this:

function indexof()
{  search="$1"; shift; arr=( $@ ) 
   for i in "${!arr[@]}"; do [ "$search" == "${arr[$i]}" ] && return $i; done
   return -1
}

Answer 1

You can calculate from the number of arguments:

seq ${#@}

Answer 2

You don't need a dummy array. You can use a counter variable:

indexof() {
    search="$1"; shift
    i=0
    for arg; do
        [ "$search" = "$arg" ] && return $i
        ((i++))
    done
    return -1
}

Note that for arg; do uses "$@" by default, that's why in "$@" can be omitted.

Answer 3

For the record, in zsh, the indexOf functionality is with:

$ set foo bar baz bar foo
$ echo $@[(i)bar] $@[(I)bar]
2 4

($2 is the first match (using the i subscript flag), $4 the last match (I subscript flag)).

Answer 4

You can instead use the 'arithmetic-for' form:

indexof(){ search=$1; shift 
    for(( i=1; i<=$#; i++ )); do [[ $search == ${!i} ]] && return $i; done
    return -1 # as an old LISPer I'd prefer 0 for the notfound case
}

Not particularly better (IMO) but different.