Python 2, python 3, base64, string and bytes

  
CONVERTING BACK AND FORTH BETWEEN STRING AND BYTES:

>>> s = 'hello'
>>> s.encode()
b'hello'
>>> b = s.encode()
>>> b.decode()
'hello'
>>>  

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$ conda create --name py2 python=2

(base) ~/Desktop$ conda activate py2

By default, 'python' command runs Python 3.

(py2) ~/Desktop$ python
Python 3.8.5 (default, Jul 28 2020, 12:59:40) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

(py2) ~/Desktop$ python2
Python 2.7.18 |Anaconda, Inc.| (default, Apr 23 2020, 22:42:48) 
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import requests
Traceback (most recent call last):
  File "[stdin]", line 1, in [module]
ImportError: No module named requests
>>> 

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(py2) ~/Desktop$ pip install requests

DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
Collecting requests
  Using cached https://files.pythonhosted.org/packages/29/c1/24814557f1d22c56d50280771a17307e6bf87b70727d975fd6b2ce6b014a/requests-2.25.1-py2.py3-none-any.whl
Collecting chardet<5,>=3.0.2
  Using cached https://files.pythonhosted.org/packages/19/c7/fa589626997dd07bd87d9269342ccb74b1720384a4d739a1872bd84fbe68/chardet-4.0.0-py2.py3-none-any.whl
Collecting urllib3<1.27,>=1.21.1
  Using cached https://files.pythonhosted.org/packages/23/fc/8a49991f7905261f9ca9df5aa9b58363c3c821ce3e7f671895442b7100f2/urllib3-1.26.3-py2.py3-none-any.whl
Collecting idna<3,>=2.5
  Using cached https://files.pythonhosted.org/packages/a2/38/928ddce2273eaa564f6f50de919327bf3a00f091b5baba8dfa9460f3a8a8/idna-2.10-py2.py3-none-any.whl
Requirement already satisfied: certifi>=2017.4.17 in /home/administrator/anaconda3/envs/py2/lib/python2.7/site-packages (from requests) (2020.6.20)
Installing collected packages: chardet, urllib3, idna, requests
Successfully installed chardet-4.0.0 idna-2.10 requests-2.25.1 urllib3-1.26.3 

--- --- --- 

With Python 2

(py2) ~/Desktop$ python2

Python 2.7.18 |Anaconda, Inc.| (default, Apr 23 2020, 22:42:48) 
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import requests
>>> from base64 import b64encode as b
>>> b('hello')
'aGVsbG8='
>>>

--- --- ---

With Python 3

(py2) ~/Desktop$ python
Python 3.8.5 (default, Jul 28 2020, 12:59:40) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from base64 import b64encode as b
>>> b('hello')
Traceback (most recent call last):
  File "[stdin]", line 1, in [module]
  File "/usr/lib/python3.8/base64.py", line 58, in b64encode
    encoded = binascii.b2a_base64(s, newline=False)
TypeError: a bytes-like object is required, not 'str'
>>> b('hello'.encode())
b'aGVsbG8='
>>> b('hello'.encode()).decode()
'aGVsbG8='
>>> 

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Tags: Technology,Python,