Index Filtering

Create a function that takes two inputs: idx (an array of integers) and str (a string). The function should return another string with the letters of str at each index in idx in order.

Examples

indexFilter([7, -1, 5, 1], "She is the love of my love") ➞ "tesh"

indexFilter([4, -7, -13, -11, -2, 0], "Relax and stay calm to avoid failures") ➞ "xavier"

indexFilter([9, -9, 2, 27, 36, 6, 5, 13, -1, 2, 0, 30, 2], "That's life, I've got you under my skin") ➞ "frank sinatra"

Notes

• Indexes may not be in order or may be negative (see examples).
• The output string must always be lowercase, but the input str may not be (as in the above examples).