Python:下载底层由Python2转Python3环境更新手记

#bytes object
byte = b"byte example"

# str object
str = "str example"

# str to bytes 字符串转字节
bytes(str, encoding="utf8")

# bytes to str 字节转字符串
str(bytes, encoding="utf-8")

# an alternative method
# str to bytes 字符串转为字节
str.encode(str)

# bytes to str 字节转为字符串
bytes.decode(bytes)

# 所有Python2需要做字符集转换的，不再需要，去除。
import sys
if sys.getdefaultencoding() == 'ascii':
    reload(sys)
    sys.setdefaultencoding('utf-8')

# python2
s = 'x = 12'
def f():
    exec s
    print x

f()  # output 12

# python3
def f():
    exec(s, globals(), globals())
    print(x)

f()  # output 12

    def set_callback(self, c_callback):
        # 3.0，api改了
        if sys.version_info >= (3, 0):
            PyCapsule_GetPointer = PYFUNCTYPE(c_void_p, py_object)(('PyCapsule_GetPointer', pythonapi))
            PyCapsule_GetName = PYFUNCTYPE(c_void_p, py_object)(('PyCapsule_GetName', pythonapi))
            c_callbackaddr = PyCapsule_GetPointer(c_callback, PyCapsule_GetName(c_callback))
        else:
            PyCObject_AsVoidPtr = PYFUNCTYPE(c_void_p, py_object)(('PyCObject_AsVoidPtr', pythonapi))
            c_callbackaddr = PyCObject_AsVoidPtr(c_callback)

        CALLBACKFUNC_T = CFUNCTYPE(c_long, c_char_p, c_long)
        self.callback = CALLBACKFUNC_T(c_callbackaddr)