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# Information on binary shifts:

# https://docs.python.org/3/library/stdtypes.html#bitwise-operations-on-integer-types

# https://www.interviewcake.com/concept/java/bit-shift

def logical_left_shift(number: int, shift_amount: int) -> str:

"""

Take in 2 positive integers.

'number' is the integer to be logically left shifted 'shift_amount' times.

i.e. (number << shift_amount)

Return the shifted binary representation.

>>> logical_left_shift(0, 1)

'0b00'

>>> logical_left_shift(1, 1)

'0b10'

>>> logical_left_shift(1, 5)

'0b100000'

>>> logical_left_shift(17, 2)

'0b1000100'

>>> logical_left_shift(1983, 4)

'0b111101111110000'

>>> logical_left_shift(1, -1)

Traceback (most recent call last):

...

ValueError: both inputs must be positive integers

"""

if number < 0 or shift_amount < 0:

raise ValueError("both inputs must be positive integers")

binary_number = str(bin(number))

binary_number += "0" * shift_amount

return binary_number

def logical_right_shift(number: int, shift_amount: int) -> str:

"""

Take in positive 2 integers.

'number' is the integer to be logically right shifted 'shift_amount' times.

i.e. (number >>> shift_amount)

Return the shifted binary representation.

>>> logical_right_shift(0, 1)

'0b0'

>>> logical_right_shift(1, 1)

'0b0'

>>> logical_right_shift(1, 5)

'0b0'

>>> logical_right_shift(17, 2)

'0b100'

>>> logical_right_shift(1983, 4)

'0b1111011'

>>> logical_right_shift(1, -1)

Traceback (most recent call last):

...

ValueError: both inputs must be positive integers

"""

if number < 0 or shift_amount < 0:

raise ValueError("both inputs must be positive integers")

binary_number = str(bin(number))[2:]

if shift_amount >= len(binary_number):

return "0b0"

shifted_binary_number = binary_number[: len(binary_number) - shift_amount]

return "0b" + shifted_binary_number

def arithmetic_right_shift(number: int, shift_amount: int) -> str:

"""

Take in 2 integers.

'number' is the integer to be arithmetically right shifted 'shift_amount' times.

i.e. (number >> shift_amount)

Return the shifted binary representation.

>>> arithmetic_right_shift(0, 1)

'0b00'

>>> arithmetic_right_shift(1, 1)

'0b00'

>>> arithmetic_right_shift(-1, 1)

'0b11'

>>> arithmetic_right_shift(17, 2)

'0b000100'

>>> arithmetic_right_shift(-17, 2)

'0b111011'

>>> arithmetic_right_shift(-1983, 4)

'0b111110000100'

"""

if number >= 0: # Get binary representation of positive number

binary_number = "0" + str(bin(number)).strip("-")[2:]

else: # Get binary (2's complement) representation of negative number

binary_number_length = len(bin(number)[3:]) # Find 2's complement of number

binary_number = bin(abs(number) - (1 << binary_number_length))[3:]

binary_number = (

"1" + "0" * (binary_number_length - len(binary_number)) + binary_number

)

if shift_amount >= len(binary_number):

return "0b" + binary_number[0] * len(binary_number)

return (

"0b"

+ binary_number[0] * shift_amount

+ binary_number[: len(binary_number) - shift_amount]

)

if __name__ == "__main__":

import doctest

doctest.testmod()

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