To transform a unicode string to a byte string in Python do this:

>>> 'foo'.encode('utf_8')
b'foo'

To transform a byte string to a unicode string:

>>> b'foo'.decode('utf_8')
'foo'

1. To convert a string to bytes.

   data = ""               #string
   data = "".encode()      #bytes
   data = b""              #bytes

2. To convert bytes to a String.

   data = b""              #bytes
   data = b"".decode()     #string
   data = str(b"")         #string

str to hex:

import codecs
hexlify = codecs.getencoder('hex')
hexlify(b'Blaah')[0]

out:

b'426c616168'

hex to str:

import codecs
decode_hex = codecs.getdecoder("hex_codec")
s = decode_hex(b'426c616168')[0]

out:

b'Blaah'

https://docs.python.org/3/library/winreg.html#
https://stackoverflow.com/questions/15128225/python-script-to-read-and-write-a-path-to-registry

import winreg

REG_PATH = r"Control Panel\Mouse"

def set_reg(name, value):
    try:
        winreg.CreateKey(winreg.HKEY_CURRENT_USER, REG_PATH)
        registry_key = winreg.OpenKey(winreg.HKEY_CURRENT_USER, REG_PATH, 0, 
                                       winreg.KEY_WRITE)
        winreg.SetValueEx(registry_key, name, 0, winreg.REG_SZ, value)
        winreg.CloseKey(registry_key)
        return True
    except WindowsError:
        return False

def get_reg(name):
    try:
        registry_key = winreg.OpenKey(winreg.HKEY_CURRENT_USER, REG_PATH, 0,
                                       winreg.KEY_READ)
        value, regtype = winreg.QueryValueEx(registry_key, name)
        winreg.CloseKey(registry_key)
        return value
    except WindowsError:
        return None

#Example MouseSensitivity
#Read value 
print (get_reg('MouseSensitivity'))

#Set Value 1/20 (will just write the value to reg, the changed mouse val requires a win re-log to apply*)
set_reg('MouseSensitivity', str(10))

#*For instant apply of SystemParameters like the mouse speed on-write, you can use win32gui/SPI
#http://docs.activestate.com/activepython/3.4/pywin32/win32gui__SystemParametersInfo_meth.html

安装：https://pypi.org/project/opencv-python/
使用：https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_setup/py_table_of_contents_setup/py_table_of_contents_setup.html
示例：https://www.askaswiss.com/2016/01/how-to-create-pencil-sketch-opencv-python.html
打包 exe：https://pypi.org/project/auto-py-to-exe/

macOS 中如果安装一些修改版或破解版软件，通过拖拽方式放到 application 目录，在打开 app 的时候可能提示程序无法运行，通常我们在系统 preference - security 里可以手动允许运行，但是有时候使用这种方法也无法打开，这是由于系统识别到这个 app 可能有问题所以给它加上了 com.apple.quarantine 隔离属性阻止了他的运行。

如果我们需要运行它，就需要删除 app 的 com.apple.quarantine 属性，可以使用 xattr 来处理。

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