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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