进制: 位移操作

源码: shifting.py

# -.- coding:utf-8 -.-
from __future__ import print_function
import unittest


class TestShifting(unittest.TestCase):

    """
    位移操作:
        左移(增大):     <<
        右移(减小):     >>
    """

    def test_left_shifting_by_one(self):
        value = 1                                   # 00000001
        value <<= 1                                 # 00000010
        self.assertEqual(value, 2)

        binary_value = bin(value)                   # "0b10"
        self.assertEqual(binary_value, "0b10")

    def test_left_shifting_by_two(self):
        value = 1                                   # 00000001
        value <<= 2                                 # 00000100
        self.assertEqual(value, 4)

        binary_value = bin(value)                   # "0b100"
        self.assertEqual(binary_value, "0b100")

    def test_left_shifting_by_five(self):
        value = 1                                   # 00000001
        value <<= 5                                 # 00100000
        self.assertEqual(value, 32)

        binary_value = bin(value)                   # "0b100000"
        self.assertEqual(binary_value, "0b100000")

    def test_left_shifting_by_ten(self):
        value = 1                                   # 00000001
        value <<= 10                                # 00000100 00000000
        self.assertEqual(value, 1024)

        binary_value = bin(value)                   # "0b10000000000"
        self.assertEqual(binary_value, "0b10000000000")

    def test_right_shifting_can_not_less_than_zero(self):
        value = 1                                   # 00000001
        value >>= 10                                # 00000000
        self.assertEqual(value, 0)

        binary_value = bin(value)                   # "0b0"
        self.assertEqual(binary_value, "0b0")

    def test_right_shifting_by_one(self):
        value = 255                                 # 11111111
        value >>= 1                                 # 01111111
        self.assertEqual(value, 127)

        binary_value = bin(value)                   # "0b1111111"
        self.assertEqual(binary_value, "0b1111111")

    def test_right_shifting_by_two(self):
        value = 255                                 # 11111111
        value >>= 2                                 # 00111111
        self.assertEqual(value, 63)

        binary_value = bin(value)                   # "0b111111"
        self.assertEqual(binary_value, "0b111111")

    def test_right_shifting_by_five(self):
        value = 255                                 # 11111111
        value >>= 5                                 # 00000111
        self.assertEqual(value, 7)

        binary_value = bin(value)                   # "0b111"
        self.assertEqual(binary_value, "0b111")

测试: main.py

import unittest


TEST_MODULE = [
    "shifting",
]


if __name__ == '__main__':
    suite = unittest.defaultTestLoader.loadTestsFromNames(TEST_MODULE)
    runner = unittest.TextTestRunner(verbosity=2)
    runner.run(suite)