arrays bash function variables curly-braces

Variable for array name within curly braces (passing or printing an array in bash)

I have a code snippet to print out an array in a shell script:

for i in "${array[@]}"; do
   echo "$i"
   done
}

I wanted to create a function out of it

printArray() {
    for i in "${$1[@]}"; do
      echo "$i"
      done
}

but when I call my function with the array name (which is also available in the shell script), I get an error: ${$1[@]}: bad substitution

What I found out ist that curly braces expand first, probably trying to expand "$1[@]" literally.

I only found answers for numeric expansion like from 1 to 5. So is it possible to replace an array name with a variable inside curly braces?

I expect to be able to put a variable instead of a specific array name in my function.

Solution

Here's how I pass and print bash arrays:

Print a bash array by passing parameters by value

arrays_join_and_print.sh from my eRCaGuy_hello_world repo:

Update: even better, see: array_print.sh now, which I just wrote. Sourcing (importing) array_print.sh via . array_print.sh gives you direct access to my two print functions below.

# Function to print all elements of an array.
# Example usage, where `my_array` is a bash array:
#       my_array=()
#       my_array+=("one")
#       my_array+=("two")
#       my_array+=("three")
#       print_array "${my_array[@]}"
print_array() {
    for element in "$@"; do
        printf "    %s\n" "$element"
    done
}

# Usage

# Build an array
array1=()
array1+=("one")
array1+=("two")
array1+=("three")

# Print it
echo "array1:"
print_array "${array1[@]}"

Sample output:

array1:
    one
    two
    three

Print a bash array by passing the array by reference

print_array2() {
    # declare a local **reference variable** (hence `-n`) named `array_ref`
    # which is a reference to the first parameter passed in
    local -n array_ref="$1"

    for element in "${array_ref[@]}"; do
        printf "    %s\n" "$element"
    done
}

# Usage

print_array2 "array1"
# or
print_array2 array1

Output: same as above.

Going further:

For passing arrays as parameters in Bash, I present 3 solutions which can also be used for printing arrays: