In this **HackerRank Ruby Array - Index, Part 1 problem-solution** Array collections offer various ways to access their elements. The positions are 0 indexed. Objects of the array can be accessed using the [] method which may take various arguments, as explained below.

arr = [9, 5, 1, 2, 3, 4, 0, -1]

A number which is the position of an element

**>>arr[4]**

** => 3**

**or**

**>>arr.at(4)**

** => 3 **

A range indicating the start and the end position

**>>arr[1..3] # .. indicates both indices are inclusive. **

** => [5,1,2]**

**>>arr[1...3] # ... indicates the last index is excluded.**

** => [5,1]**

Start index and the length of the range

**>>arr[1,4]**

** => [5, 1, 2, 3]**

## Problem solution.

def element_at(arr, index) arr[index] end def inclusive_range(arr, start_pos, end_pos) arr[start_pos..end_pos] end def non_inclusive_range(arr, start_pos, end_pos) arr[start_pos...end_pos] end def start_and_length(arr, start_pos, length) arr[start_pos,length] end

## Second solution.

def element_at(arr, index) # return the element of the Array variable `arr` at the position `index` # arr.at(index) # or arr[index] end def inclusive_range(arr, start_pos, end_pos) # return the elements of the Array variable `arr` between the start_pos and end_pos (both inclusive) arr[start_pos,(end_pos-start_pos+1)] end def non_inclusive_range(arr, start_pos, end_pos) # return the elements of the Array variable `arr`, start_pos inclusive and end_pos exclusive arr[start_pos,end_pos-start_pos] end def start_and_length(arr, start_pos, length) # return `length` elements of the Array variable `arr` starting from `start_pos` arr[start_pos,length] end

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