How To Install Python Packages – Part VI

See the previous installment in this series here to learn how to check the version of a Python package.

Things to note

1. Pip installs the latest version of the package by default.
2. While installing the specific version pip replaces the existing version if there is any.
3. You can use the above syntax for installing the packages through IPython notebook.
4. If you wish to install using command prompt you can use the same syntax by just removing the exclamation mark.

For example,

• IPython notebook: `!pip install package_name`
• Command prompt: `pip install package_name`

I hope this will clarify any queries or doubts that you might have about installing Python packages. One of the popular ways to traverse through the Python codes and packages is the dir() function. Let’s learn more about what it does in the next section of the tutorial on ‘how to install Python packages’.

Bonus: dir()function

We can use the built-in function dir() to find which names a module defines. It returns a sorted list of strings.

In []: import arithmetic
In []: dir(arithmetic)
Out[]:
[‘__builtins__’,
‘__cached__’,
‘__doc__’,
‘__file__’,
‘__loader__’,
‘__name__’,
‘__package__’,
‘__spec__’,
‘addition’,
‘division’,
‘factorial’,
‘multiply’]
dir()function | 61

Here, we can see a sorted list of names within the module arithmetic. All other names that begin with an underscore are default Python attributes associated with the module (we did not define them).

Without arguments, dir() lists the names we have defined currently:

In []: a = 1
In []: b = ‘string’
In []: import arithmetic
In []: dir()

Out[]:
[‘__builtins__’,
‘a’,
‘arithmetic’,
‘b’,
‘exit’,
‘Quit’]

Stay tuned for the next installment, in which the authors will discuss how to address queries in Python.

Visit QuantInsti website to download readily available Python commands.