I'm learning shall scripting, and I wonder if there's any way to add numbers to an element of an array so that the number would be added to the element instead of appending it.
num=1
declare -A array
array[0]+=$num
array[0]+=$num
echo ${array[0]}
obviously, the result would be '11' instead of 2. I know this question might exists in the community, but I couldn't find it maybe because I don't know how to name the problem.
You can use arithmetic context ((..)):
num=1
declare -A array
((array[0]+=$num))
((array[0]+=$num))
echo ${array[0]}
2
Giving the array the integer attribute enables "bare" arithmetic:
num=1
declare -Ai array
array[0]+=$num
array[0]+=num # also works without expanding the variable
# because this is arithmetic evaluation
declare -p array
outputs
declare -Ai array=([0]="2" )
-A defines an associative array. -i also works with -a numerically-indexed arrays.
