Associative arrays (declare -A) in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of Associative Array Access

What is the output of this Bash script?

Bash Scripting

declare -A colors
colors[apple]=red
colors[banana]=yellow
colors[grape]=purple
echo ${colors[banana]}

A yellow

B red

C purple

D banana

💡 Hint

Look at the key used inside the brackets when accessing the array.

The script declares an associative array 'colors' and assigns colors to fruits. Accessing colors[banana] prints 'yellow'.

💻 Command Output

intermediate

Count Items in Associative Array

What is the output of this Bash script?

Bash Scripting

declare -A animals
animals[dog]=bark
animals[cat]=meow
animals[cow]=moo
animals[duck]=quack
echo ${#animals[@]}

A 4

B 3

C 0

D 1

💡 Hint

${#array[@]} gives the number of elements in the array.

The associative array 'animals' has 4 key-value pairs, so ${#animals[@]} outputs 4.

🔧 Debug

advanced

Identify the Error in Associative Array Declaration

What error does this Bash script produce?

Bash Scripting

colors=( [red]=apple [yellow]=banana )
echo ${colors[red]}

A bash: colors: unbound variable

B bash: colors: array assignment without declare -A

C bash: colors: command not found

D No error, outputs 'apple'

💡 Hint

Associative arrays require a special declaration in Bash.

Associative arrays must be declared with 'declare -A' before assigning key-value pairs. Without it, Bash treats it as a normal array and errors.

🚀 Application

advanced

Result of Looping Over Associative Array Keys

What will this Bash script output?

Bash Scripting

declare -A capitals
capitals[France]=Paris
capitals[Japan]=Tokyo
capitals[India]=NewDelhi
for country in "${!capitals[@]}"; do
  echo "$country: ${capitals[$country]}"
done

A Paris Tokyo NewDelhi

B

Paris: France
Tokyo: Japan
NewDelhi: India

C

France: Paris
Japan: Tokyo
India: NewDelhi

D France Japan India

💡 Hint

"${!array[@]}" gives all keys in the associative array.

The loop iterates over keys (countries) and prints each key with its value (capital). Output is each country and its capital separated by colon.

🧠 Conceptual

expert

Behavior of Unset Key in Associative Array

What is the output of this Bash script?

Bash Scripting

declare -A fruits
fruits[apple]=red
fruits[banana]=yellow
unset fruits[apple]
echo ${fruits[apple]:-none}

A yellow

B red

C banana

D none

💡 Hint

Unset removes the key, and the default value is used if key is missing.

The key 'apple' is removed with unset. Accessing fruits[apple] returns empty, so the default 'none' is printed.