Anaconda is a Data Science Python Distribution which includes:
- Python
- Python Standard Modules
- The Numeric Python library – numpy
- The Python and Data Analysis library – pandas
- The matrix plotting library – matplotlib
This tutorial will look at importing these modules and libraries and what it means physically.
Anaconda PowerShell Prompt
Open the Anaconda PowerShell Prompt from the Start Menu:
By default it will open in %USERPROFILE%:
Notice the Anaconda PowerShell Prompt begins with (base), this means the (base) Python environment is selected:
This is the python.exe found in the Anaconda3 folder:
The Anaconda PowerShell Prompt uses the Programming Language PowerShell PS by default:
The > indicates a new prompt:
The command prompt has the following syntax:
command option -p parametervalue1
command option --parametername2 parametervalue2
command option --parametername3
Python
To launch Python from the Anaconda PowerShell Prompt input:
python
Notice details about the Python version display alongside a new Prompt >>>.
Python uses the following functional syntax which is different to the command line syntax seen above:
function(value1, arg2=value2)
Note that these are two different programming languages.
Importing Libraries
Notice the base Python environment has a Lib folder:
This contains the Python standard modules such as email:
If the module is examined it has a __init__.py file which is the default Python file imported when a folder is referenced.
The module can be imported using:
import email
And the path of the physical file can be examined using the data model attribute __file__:
email.__file__
Note every \ is replaced with \\, as \ is used to insert an escape character in a Python string, in this case the escape character to be inserted is also \.
The email standard module has submodules which can also be accessed using a . and in Python the . essentially means belonging to this object. Note that the .py file extension is not included in an import statement and therefore there is no confusion with the . used to indicate a file extension.
For example:
email.charset
would reference the charset.py in this email folder.
Some standard modules are smaller and are not contained in a folder. For example the datetime module is a single datetime.py file:
It can be imported and details of its file can be examined using:
import datetime datetime.__file__
The third-party data science libraries are found in the site-packages folder:
There is normally a folder that is the name of the library containing the Python script files alongside a folder that states the version:
The numpy library has a __init__.py file which is the Python file imported when numpy is imported:
As numpy is very commonly used it is typically imported using the 2 letter alias:
import numpy as np np.__file__
The pandas library has a __init__.py file which is the Python file imported when pandas is imported:
As pandas is very commonly used it is typically imported using the 2 letter alias:
import numpy as pd pd.__file__
The matplotlib library has a __init__.py file:
However typically only a module of this library is used called pyplot:
As pyplot is very commonly used it is typically imported using the 4 letter alias:
import matplotlib.pyplot as plt plt.__file__
The locations of these modules and libraries can be seen together:
To exit python use the function exit:
Notice because this is a function it is followed by parenthesis.
To exit the Anaconda PowerShell Prompt use the command exit:
Notice there is no parenthesis.
There is a difference in syntax as Python and PowerShell are two different programming languages.
