Showing python module help or documentation inside Python Intrepeter in good display / format


When we need to import some python modules, sometimes we need to read the documentation inside the python intrepeter.
There are 2 ways to showing help / documentation of the module.

1. __doc__
We can see by print attribute “__doc__” from the module. Example, I use module “copy”:

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import copy

print(copy.__doc__)
Generic (shallow and deep) copying operations.

Interface summary:

        import copy

        x = copy.copy(y)        # make a shallow copy of y
        x = copy.deepcopy(y)    # make a deep copy of y

For module specific errors, copy.Error is raised.

The difference between shallow and deep copying is only relevant for
compound objects (objects that contain other objects, like lists or
class instances).

– A shallow copy constructs a new compound object and then (to the
  extent possible) inserts *the same objects* into it that the
  original contains.

– A deep copy constructs a new compound object and then, recursively,
  inserts *copies* into it of the objects found in the original.

Two problems often exist with deep copy operations that don’t exist
with shallow copy operations:

 a) recursive objects (compound objects that, directly or indirectly,
    contain a reference to themselves) may cause a recursive loop

 b) because deep copy copies *everything* it may copy too much, e.g.
    administrative data structures that should be shared even between
    copies

Python’s deep copy operation avoids these problems by:

 a) keeping a table of objects already copied during the current
    copying pass

 b) letting user-defined classes override the copying operation or the
    set of components copied

This version does not copy types like module, class, function, method,
nor stack trace, stack frame, nor file, socket, window, nor array, nor
any similar types.

Classes can use the same interfaces to control copying that they use
to control pickling: they can define methods called __getinitargs__(),
__getstate__() and __setstate__().  See the documentation for module
"pickle" for information on these methods.


2. Using help
The another way to show complete documentation of this module, we can use help().

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Help on module copy:

NAME
    copy – Generic (shallow and deep) copying operations.

FILE
    /usr/lib64/python2.7/copy.py

DESCRIPTION
    Interface summary:
   
            import copy
   
            x = copy.copy(y)        # make a shallow copy of y
            x = copy.deepcopy(y)    # make a deep copy of y
   
    For module specific errors, copy.Error is raised.
   
    The difference between shallow and deep copying is only relevant for
    compound objects (objects that contain other objects, like lists or
    class instances).
   
    – A shallow copy constructs a new compound object and then (to the
      extent possible) inserts *the same objects* into it that the
      original contains.

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