Python future module

#python #builtin #modules #functional

Originally posted on Ashraful's Blog

❓ What is future module btw?

future is python built-in module.
It serves three purposes,
To avoid confusing existing tools that analyze import statements and expect to find the modules they’re importing.
To ensure future statements run under release prior to 2.1 at least yield runtime exceptions
future will allow you to use a feature from the future.

I know it sounds crazy for the first time you heard. But it's real. Let's dig into this.

🔥 More about future.

future module introduced from python 2.1. On the source of cpython's __future__.py there is defined each future feature like following,

FeatureName = _Feature(OptionalRelease, MandatoryRelease, CompilerFlag)

Where, normally, OptionalRelease is less than MandatoryRelease, and both are 5-tuples of the same form as sys.version_info

sys.version_info(major=3, minor=8, micro=1, releaselevel='final', serial=0)

💥 Okay! Enough talk. Let's see the usage.

Suppose, you are using python2(Though python 2 is dead. Just take it an example). You want to use the print function from python3. But how you can do it? Here comes the future module.

Python 3 Console

>>>
>>> print('Hello', 'World', sep=', ', end='\n')
Hello, World
>>>
>>>

In python2 you need to do the following,

>>>
>>> from __future__ import print_function
>>>
>>> print('Hello', 'World', sep=', ', end='\n')
Hello, World
>>>

Here, I have imported print_fuction from future module. Then it's working as expected from python3. I hope you got it.

😳 Available future functions

nested_scopes
generators
division
absolute_import
with_statement
print_function
unicode_literals
barry_as_FLUFL
generator_stop
annotations