why the function below "print(list(vague_list))" generates a list consisting of 4 up to 6 elements each being randomly chosen fr

Question

Hi all,
Please kindly help to understand why the function below "print(list(vague_list))" generates a list consisting of 4 up to 6 elements each being randomly chosen from the initial list ["A", "B", "C", "D", "E"]?

quote
import random
class VagueList:
def __init__(self, cont):
self.cont = cont

def __getitem__(self, index):
return self.cont[index + random.randint(-1, 1)]

def __len__(self):
return random.randint(0, len(self.cont)*2)

vague_list = VagueList(["A", "B", "C", "D", "E"])
print(list(vague_list))
unquote

Possible outputs:
['E', 'C', 'C', 'D'], or
['E', 'C', 'C', 'D', 'E'], or
['E', 'C', 'C', 'D', 'E', 'E'], etc.

Why and how it works?

Answer 1

Hi,
print(list(vague_list)) is equal to print VagueList[0] to VagueList[4] by call to function __getitem__(index)
So, a random value (-1, 0 or 1) is added to index (0 to 4)
While (index + random.randint(-1, 1)) <5, __getitem__ is called
Sometimes, returns 4 values, when random = 1
...
I hope that explain is good for you
Mbzh31