🔒 Python enumeration error

[night moat]

really unsure as to why the enumeration command isn't creating a list of items here? https://www.codewars.com/kata/5566b0dd450172dfc4000005/train/python
My Code:

def length_of_sequence(arr,n):
    index = [i for i, e in enumerate(arr) if e == n ]
    print(index)
    return arr[(index.pop(0)):(index.pop(-1))]

Test:

@test.describe("Fixed Tests")
def fixed_tests():
    @test.it('Basic Test Cases')
    def basic_test_cases():
        test.assert_equals(length_of_sequence([1], 0), 0, 'Returns zero when the element is not found in the array')
        test.assert_equals(length_of_sequence([1], 1), 0, 'Returns zero with only one element in the array')
        test.assert_equals(length_of_sequence([1, 1], 1), 2, 'Returns two when there are only two elements in the array');
        test.assert_equals(length_of_sequence([1, 2, 3, 1], 1), 4, 'Returns four for an array of length four and the number to be searched at the boundaries');
        test.assert_equals(length_of_sequence([-7, 5, 0, 2, 9, 5], 5), 5, 'Returns five');
        test.assert_equals(length_of_sequence([-7, 6, 2, -7, 4], -7), 4, 'Returns four');
        test.assert_equals(length_of_sequence([0, 8, -7, 6, 1, 2, -7, 4, 8, 9], 8), 8, 'Returns eight')
        test.assert_equals(length_of_sequence([-7, 3, -7, -7, 2, 1], -7), 0, 'Returns zero as when there are more than two instances')
        test.assert_equals(length_of_sequence([-7, 3, -7, -7, 2, -7], -7), 0, 'Returns zero as when there are more than two instances')

[sharp kayak]

@night moat

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[celest ruin]

!code please

[sharp kayak]

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[celest ruin]

Use ```py
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```

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those are backticks, not quotes

[night moat]

Done :)

[celest ruin]

What is your function supposed to do?

[night moat]

It's meant to create a list based on the list provided where it starts at the first instance of an integer n and ends at the final instance of that integer, creating a subsection

but I'm making the more basic mistake of not making a list at all unfortunately

[celest ruin]

so if the array has no value n, it creates an empty list?

[night moat]

hmmm I guess so? I haven't really thought about that

[celest ruin]

and doing [].pop(0) raises an error

[night moat]

yeah because it's an empty list

[celest ruin]

so your first asert of length_of_sequence([1], 0) should raise IndexError

[night moat]

Traceback (most recent call last):
  File "/workspace/default/.venv/lib/python3.11/site-packages/codewars_test/test_framework.py", line 112, in wrapper
    func()
  File "/workspace/default/tests.py", line 8, in basic_test_cases
    test.assert_equals(length_of_sequence([1], 0), 0, 'Returns zero when the element is not found in the array')
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/workspace/default/solution.py", line 4, in length_of_sequence
    return arr[(index.pop(0)):(index.pop(-1))]
                ^^^^^^^^^^^^
IndexError: pop from empty list

[night moat]

as in because it tried to remove a value that isn't there?

[celest ruin]

Yes.

You should add a check for that.

if it's length 0, return an empty list. if length 1, return [n]. otherwise do as normal

[night moat]

and that's at the core of the problem here, the enumeration is fine?

[celest ruin]

yes.

[night moat]

okay, I will try adding a check!

awesome I misunderstood the question since it turns out it was asking for length but yeah the check was something I was missing and was the reason fro that error above

thanks!

[sharp kayak]

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