def int_to_trit(i, t_arr):
  if i < 0:  # Special case for handling negatives: just flip all the trits in the positive version
    # return [-x for x in int_to_trit(-i, t_arr)]  # the Python way of doing the following:
    negative_result = int_to_trit(-i, t_arr)  # Store the result of running this against a positive number
    for i in range(len(negative_result)):  # For each index in the negative_result array,
      negative_result[i] *= -1  # negate the stored value
    return negative_result  # Return the results
  if i == 0:  # Termination case
    return t_arr if len(t_arr) > 0 else [0]  # Usually, avoid leading 0's, but I had to add an extra condition for calls of int_to_trit(0, [])
  r = abs(i % 3)  # Python % always returns a positive number; C does not so some logic below will need changed
  # print "{} % 3 == {}".format(i, r)  # for debug
  if r == 2:
    t_arr.insert(0, -1)  # insert(0, x) simply means to append to the beginning of a list in Python. If using an actual array, this could be accomplished by allocating a new array of size n + 1, setting the first value to -1, and copying the array of size n after the -1 value. Alternatively, the C implementation may allocate an array with 5 indices for this method and pass the current index as a parameter.
    i += 1  # I don't know the best way to describe why we have to do this. Think of the case of 2 though. 2 in ternary is represented as [1, -1]; it's 3 - 1. Since 2 is "1 short" of 3, we need to add one to our accumulator.
  elif r == 1:
    t_arr.insert(0, 1)  # Theoretically, we could subtract one from i as we did above, but it won't do anything due to floor division.
  else:
    t_arr.insert(0, 0)
  return int_to_trit(i // 3, t_arr)  # The // operator in Python emphasizes integer division (floors the result)

>>> int_to_trit(0, [])
[0]
>>> int_to_trit(1, [])
[1]
>>> int_to_trit(2, [])
[1, -1]
>>> int_to_trit(3, [])
[1, 0]
>>> int_to_trit(72, [])
[1, 0, -1, 0, 0]
>>> int_to_trit(121, [])
[1, 1, 1, 1, 1]
>>> int_to_trit(-121, [])
[-1, -1, -1, -1, -1]
>>> int_to_trit(-72, [])
[-1, 0, 1, 0, 0]
>>> int_to_trit(-3, [])
[-1, 0]
>>> int_to_trit(-2, [])
[-1, 1]
>>> int_to_trit(-1, [])
[-1]

# With debug
>>> int_to_trit(72, [])
72 % 3 == 0
24 % 3 == 0
8 % 3 == 2
3 % 3 == 0
1 % 3 == 1
[1, 0, -1, 0, 0]