What is the meaning of myarr. length -1?

Question

How should we use it?

Answer 1

One less than the length of the myarr array.

Answer 2

Length is a final variable applicable for arrays. It helps to get the size of the array. "myarr" must be an array. And that - 1reduces the size of array by 1.
If you want to get number of characters in a string than you can use length().

Answer 3

means array length - 1
Example:
if your array has length = 5
if you use method (.length) - 1
means = 4

Answer 4

I think it can be used

to delete a letter from word.
Mean it is part of code for backspace button.