[Python Tips] Getting Help

8 comments

themarkymark
74
6 months agoBusy4 min read

There are a few handy functions built into Python to help the developer get more information about an object.

help()

If you want to get the documentation on an object or function you can use the help() function to look up any documentation available.

> help(id)
Help on built-in function id in module builtins:
>>> 
id(obj, /)
    Return the identity of an object.  
    This is guaranteed to be unique among simultaneously existing objects.
    (CPython uses the object's memory address.)

This is only useful when using python interactively via repl or bpython.

dir()

When you call dir() without any arguments, it will return the names of everything in scope.

>>> dir()
['__builtins__', '__doc__', '__name__', 'help']
>>> a = 5
>>> dir()
['__builtins__', '__doc__', '__name__', 'a', 'help']

If you call dir on an object, it will return all the available attributes.

>>> a = 'Hello World'
>>> dir(a)
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init
_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__',
 '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isdecimal', 'isdigit', 'isidentifier', '
islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 
'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']

dir() is also most useful when using python interactively.

While both of these functions are not typically used on a daily basis, knowing they are available can be helpful when working interactively. I typically work interactively when doing querying or working with objects I don't understand yet to get a feel for how they work. This is where bypython shines.

As always, the Python Online Docs is a great reference when trying to understand how the built-in functions and objects work. They can be difficult to understand to new programmers and just doing a Google search for what you need help with and then clicking videos usually yields the best results. Almost every topic has been covered in detail in a YouTube video.

Good Python YouTubers I highly recommend.

If you haven't already, consider opening an account on StackOverflow the most popular Q&A site for developers across the world.

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