Often you may want to iterate over an associative array in Bash.
You can use the following methods to do so:
Method 1: Access Keys of Associative Array
echo "${!my_array[@]}"
This particular example will return all of the keys from the associative array named my_array.
Method 2: Access Values of Associative Array
echo "${my_array[@]}"
This particular example will return all of the values from the associative array named my_array.
Method 3: Access Both Keys and Values of Associative Array
for i in "${!my_array[@]}"
do
echo "$i: ${my_array[$i]}"
done
This particular example will return each key and value (separated by a colon) from the associative array named my_array.
The following example shows how to use each of these methods in practice.
Example: How to Iterate Over Associative Array in Bash
Suppose that create an associative array named my_array in Bash in which the keys are the names of cities and the values are the names of professional basketball teams in those cities:
declare -A my_array=( [Dallas]=Mavs [Miami]=Heat [Orlando]=Magic )
We can use the following syntax to return all of the keys from this associative array:
echo "${!my_array[@]}"
The following screenshot shows how to use this syntax in practice:
We can also use the following syntax to return all of the values from this associative array:
echo "${my_array[@]}"
The following screenshot shows how to use this syntax in practice:
Lastly, we can use the following syntax to iterate over the associative array and return both the keys and the values:
for i in "${!my_array[@]}"
do
echo "$i: ${my_array[$i]}"
done
The following screenshot shows how to use this syntax in practice:
Notice that this returns each key and value in the associative array.
Feel free to replace the colon ( : ) in the echo statement to instead return the keys and values separated by a different delimiter.
Related Tutorials
The following tutorials explain how to perform other common tasks in Bash:
Bash: How to Split a String into an Array
Bash: How to Remove Last Element from Array
Bash: How to Find Minimum and Maximum Values in Array
