Python 2x -> 3.x

  Nowadays, Python 3 is becoming more and more popular than Python 2, but there are still a lot of codes of Python 2 remained. Although we can use them on Python 2 or use pyenv to manage the versions of Python, but I still want to modify these codes to make them runnable in python 3.

  2016/05/31: Hot, 22 - 34 ℃, Light rain, Tuesday

  1.str and bytes(type in python)

  In Python 2, str are given equal treatment to bytes, absolutly. In my opinion, I don't think it is good. String is a explicit entity of bytes, and bytes is inner entity of string.

  We can easily declare a bytes value from a const string. Example: kom_header = b"KOG GC TEAM MASSFILE V.0.3."

  Convert

  str->decode->bytes

    example: s = b'x6dx61x69x6Bx61x7Ax65'

                   s.decode('utf-8')

  bytes->encode->encoding

    example: bytes(str, encoding = encoding_page)

  Attention:

    In Python 3, we should open a binary file in binary mode, instead of text mode.

  2.xrange() and range()

     In Python 2, there is some differences between xrange() and range(), which cause some unfair treatment to range()(QAQ,in perfermance),but now these differences are disappeared in Python 3. We can use range()(in fact, it is xrange()) only in Python 3, xrange() get the formal position to replace range().And range() function has died.(pupu).

    Now range() will make a iterator (on rules) instead of a list.