Packages

Intermediate Python for Developers

Jasmin Ludolf

Senior Data Science Content Developer

Modules are Python files

Module = Python file
Anyone can create a Python file!

Code file on a laptop

Packages

A collection of modules = Package
- Also called a library
Publicly available and free
Downloaded from PyPI
Then can be imported and used like modules

Large cardboard box

¹ https://pypi.org/

Installing a package

Terminal / Command Prompt
```
python3 -m pip install <package_name>
```
python3 - executes Python code from the terminal
pip - preferred installer

Coding terminal

Installing a package

python3 -m pip install pandas

Pandas logo

Package for data manipulation and analysis

Importing with an alias

# Import pandas
import pandas

Use an alias to shorten the code

# Import pandas using an alias
import pandas as pd

Creating a DataFrame

# Sales dictionary
sales = {"user_id": ["KM37", "PR19", "YU88"],
         "order_value": [197.75, 208.21, 134.99]}


# Convert to a pandas DataFrame
sales_df = pd.DataFrame(sales)


print(sales_df)

  user_id  order_value
0    KM37       197.75
1    PR19       208.21
2    YU88       134.99

Reading in a CSV file

# Reading in a CSV file in our current directory
sales_df = pd.read_csv("sales.csv")


# Checking the data type
print(type(sales_df))

pandas.core.frame.DataFrame

Previewing the file

# DataFrame method to preview the first five rows
print(sales_df.head())

  user_id  order_value
0    KM37       197.75
1    PR19       208.21
2    YU88       134.99
3    NT43       153.54        
4    IW06       379.47

Checking the file info

# Checking the file info
print(sales_df.info())

RangeIndex: 3 entries, 0 to 2
Data columns (total 2 columns):
 #   Column       Non-Null Count  Dtype  
<hr />  ------       --------------  -----  
 0   user_id      3 non-null      object 
 1   order_value  3 non-null      float64
dtypes: float64(1), object(1)
memory usage: 180.0+ bytes

Functions versus methods

# This is a built-in function
print(sum([1, 2 ,3, 4, 5]))

Function = code to perform a task

# This is a pandas function
sales_df = pd.DataFrame(sales)

.head() only works with pandas DataFrames

# This is a method
print(sales_df.head())

  user_id  order_value
0    KM37       197.75
1    PR19       208.21
2    YU88       134.99
3    NT43       153.54        
4    IW06       379.47

Method = a function that is specific to a data type

Let's practice!

Intermediate Python for Developers