通过索引数组访问嵌套元素

Question

I have two arrays

• dataArr - An array containing an unknown number of arrays and objects that may contain an unknown number of arrays and objects and so on. The array may also contain properties at various levels (think nested JSON)
• indexArr - An array of length n containing the keys to access a specific item in dataArr

How would I go about retrieving, adding and updating values in dataArr[indexArr[0]][indexArr[1]][indexArr[2]]...[indexArr[n]] without creating a new array?

Languages of interest: javascript and python .

Answer 1

Create recursive function that you pass in indexes array and origin array.

function getItem(data, indexes) {
    if (indexes.length) {
        var index = indexes.shift();

        // if index exist - dive deeper, else return indicator that failed.
        if (typeof data[index] !== 'undefined') {
            return getItem(data[index], indexes);
        } else {
            return null;
        }
    }

    // will be returned when no more indexes passed - last element reached
    return data;
}

getItems(dataArr, [1, 5, 9, 'a', 'sum', 99]);