CODEWITHSUNDEEP
bash
Sanborn Nguyen
Sanborn Nguyen

Reputation: 25

How do I use a for loop to update an array's element at the i'th index?

I'm trying to loop through an array and update the element at the i'th index. I've tried several ways but they've all resulted in an error.

Here I'm trying to increment each element by one.

TEST_ARR=(0 1 2 3 4 5 6 7 8 9)

for (( i=0; i<${#TEST_ARR[@]}; i++ )); do
    ${TEST_ARR[$i]}++
done

Here I'm trying to set each element to a different value.

TEST_ARR=(0 1 2 3 4 5 6 7 8 9)

for (( i=0; i<${#TEST_ARR[@]}; i++ )); do
    ${TEST_ARR[$i]}=0
done

Upvotes: 1

Views: 40

Answers (1)

Barmar
Barmar

Reputation: 781706

You need to put arithmetic expressions inside (()).

When you're assigning to a variable, you don't put $ before it.

for (( i=0; i<${#TEST_ARR[@]}; i++ )); do
    ((TEST_ARR[$i]++))
done

for (( i=0; i<${#TEST_ARR[@]}; i++ )); do
    TEST_ARR[$i]=0
done

Upvotes: 3

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