> ## Documentation Index
> Fetch the complete documentation index at: https://blog.sumathi.dev/llms.txt
> Use this file to discover all available pages before exploring further.

#  Arrays

* collection of items (boolean , objects  , strings)
* Arrays are mutable , you can change any value
* Array are objects , typeof return objects
* ```js theme={null}
    let marks_class_10 = [1,2,3,4, null, false , "Not present"];
    console.log(marks_class_10)
    console.log(marks_class_10[7]) // will be undefined beacuse index does not exits
    console.log("Length of array is "+marks_class_10.length)

    // modifying value
    marks_class_10[7] = 89 // Addding a new value to array
    console.log(marks_class_10[7])
    marks_class_10[1] = 98 // Modifying value , Arrays are mutable
    console.log(marks_class_10)
    console.log(typeof marks_class_10)
  ```