Associative Array with List of Files as Values …

Question

I'm having some Trouble with Bash's associative Arrays: I'm looking for a Solution to assign an Array with Filenames to the associative Array.

It should look like :

/Applications/Setup.app => ([0] = "/Applications/Setup.app/[email protected]"
                            [1] = "/Applications/Setup.app/[email protected]"
                            [2] = "/Applications/Setup.app/IDMusic [email protected]")

Declaring the Dictionary / Hash Table / Associative Array isn't the Problem :

declare -A Dictionary

To get the Keys I'm using "readarray", combined with "find" :

readarray -d '' Applications < <(find "/Applications" -name "*.app" -print0)

If a Directory has a Whitespace in it's Name it's not a Problem. Now I need to find the PNG-Files in Application's Directory :

if [ ${#Applications[*]} -gt 0 ]; then
    for App in "${Applications[@]}"; do
        readarray -d '' Files < <(find "$App" -iname "*.png" -type f -print0)

        for File in "${Files[@]}"; do
            Dictionary["$App"]+="$File"
        done
    done
fi

The Problem which I didn't understand is, how can I add the Result of second "find" to the declared associative Array as List of Files ? If I set the readarray with Delimiter ' ' some Files, containing Whitespaces, were broken.

The next Question is how can I get the Values in a for-Loop ? I tried this also with readarray, but this didn't work for Files with Whitespaces in it's Name.

for Key in "${!Dictionary[@]}"; do
    readarray -d ' ' Values <<< "${Dictionary[$Key]}"

    for Value in "${Values[@]}"; do
        echo "$Value"
    done
done

If I run the above Script this is what I get :

/Applications/Setup.app/[email protected]/Applications/Setup.app/[email protected]/Applications/Setup.app/IDMusic 
[email protected]

But I want this One :

/Applications/Setup.app/[email protected]
/Applications/Setup.app/[email protected]
/Applications/Setup.app/IDMusic [email protected]

Is there any Chance getting this Work with Bash 5.0.3 ?

The Goal is to use most of the Features without awk / grep / sed, so it runs with Bash's Built-In Commands.

The only idea I have is to store the lists in a format like JSON, using a tool like jq. But really, if you need 2-dimensional arrays, you shouldn't be using bash in the first place. Use a programming language with real data structures. — Barmar
– Barmar, Commented Jan 7, 2021 at 16:21

markp-fuso · Accepted Answer · 2021-01-07 16:48:30Z

When populating the array with the filenames, consider using a character (as a delimiter) that does not exist in any of the filenames. [NOTE: as currently coded there is no delimiter hence the reason the filenames are jammed together as a single long line].

For example, assuming the filenames do not contain a linefeed (\n), and assuming the find returns the following:

/Applications/Setup.app/[email protected]
/Applications/Setup.app/[email protected]
/Applications/Setup.app/IDMusic [email protected]

We can populate the array like such:

unset      Dictionary
declare -A Dictionary

App="/Applications/Setup.app"

# for sake of example, simulate find results by processing a list of files

for file in "/Applications/Setup.app/[email protected]" "/Applications/Setup.app/[email protected]" "/Applications/Setup.app/IDMusic [email protected]"
do
    Dictionary[${App}]+=$'\n'"${file}"     # use '\n' as delimiter
done

while IFS=$'\n' read -r line
do
    [[ -n "${line}" ]] &&                  # skip the initial '\n'
    printf "|%s|\n" "${line}"
done <<< "${Dictionary[@]}"

NOTE: pipes added to printf format as visual delimiters

This generates:

|/Applications/Setup.app/[email protected]|
|/Applications/Setup.app/[email protected]|
|/Applications/Setup.app/IDMusic [email protected]|

Ivan · Accepted Answer · 2021-01-07 18:21:39Z

0

Aray of arrays, consider this approach:

[[ ${Applications[@]} ]] && {
    for i in "${!Applications[@]}"; do
        readarray -d '' "Files$i" < <(find "${Applications[$i]}" -iname "*.png" -type f -print0)
        Dictionary["${Applications[$i]}"]="Files$i"
    done
}

And then to retrive values use this:

for key in "${!Dictionary[@]}"; do
    val="${Dictionary[$key]}[@]"
    echo "$key: ${!val}"
done

And check here

edited Jan 7, 2021 at 18:21

answered Jan 7, 2021 at 18:12

Ivan

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Comments

tshiono · Accepted Answer · 2021-01-08 03:26:39Z

By just modifying Ivan's nice answer, how about:

declare -A Dictionary
readarray -d '' Applications < <(find "/Applications" -name "*.app" -print0)

for i in "${!Applications[@]}"; do
    readarray -d '' "Files$i" < <(find "${Applications[$i]}" -iname "*.png" -type f -print0)
    Dictionary["${Applications[$i]}"]="Files$i"
done

for key in "${!Dictionary[@]}"; do
    echo "$key => "
    declare -n ary="${Dictionary[$key]}"
    for j in "${!ary[@]}"; do
        echo "  [$j] = ${ary[j]}"
    done
done

As an example, if we have a directory tree as follows:

/Applications/
├── Bar.app
│   ├── bar1.png
│   └── bar2.png
├── Foo.app
│   ├── foo1.png
│   └── foo2.png
└── Setup.app
    ├── [email protected]
    ├── IDMusic [email protected]
    └── [email protected]

The result will be:

/Applications/Foo.app => 
  [0] = Applications/Foo.app/foo1.png
  [1] = Applications/Foo.app/foo2.png
/Applications/Bar.app => 
  [0] = Applications/Bar.app/bar1.png
  [1] = Applications/Bar.app/bar2.png
/Applications/Setup.app => 
  [0] = Applications/Setup.app/[email protected]
  [1] = Applications/Setup.app/IDMusic [email protected]
  [2] = Applications/Setup.app/[email protected]

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