input: Write a function to populate an array with random numbers from 1 to 100 according to a given array length. If the array length is 0, return an empty array.
  
  assert populateArray(5)
  assert populateArray(0)==[]
  assert len(populateArray(10))==10
output: import random
  
  def populateArray(length):
      if length == 0:
          return []
      return [random.randint(1, 100) for _ in range(length)]