# Python create a package

Topics we discuss here

- **Why we need a package ?**

- **How to create a package?**

### Package?
 Consider you have a bunch of files  which is having the common functionality or logic implemented in it , when we want to use it in our existing code either we need to point out the folder by **sys.path.append **or we need to copy the whole files into current directory 


```
sys.path.append("path of common files ")

``` 
For avoiding this we need package

### How to create a package?

Here We need to follow a structure, if a folder contains a dunder init we call it as a package in the same we need to directories and a setup.py and remaining other common py files


```
package_directory(article)
   | package(article)
        | __init__.py
        | pipeline_selector.py
        | executor.py
        | submodule(constants)
              | key_constants.py
   | README.md
   | setup.py

``` 



```
# pipeline_selector.py

def pipelines(details):
    print(details)

``` 

```
#executor.py
from article.pipline_selector import pipeline

def execute():
    pipeline("i am from executor")

``` 


> When ever we import a function inside other file please use relative import like  above

#### setup.py example structure
```
import setuptools
from setuptools import find_packages
from os import path

with open("README.md", "r") as fh:
    long_description = fh.read()


setuptools.setup(
    name="article",  # Replace with your own username
    version="0.0.1",
    author="Venkatesh",
    author_email="email.com",
    description="example lib",
    long_description=long_description,
    long_description_content_type="text/markdown",
    url="#",
    packages=setuptools.find_packages(),
    classifiers=[
        "Programming Language :: Python :: 3",
        "License :: OSI Approved :: MIT License",
        "Operating System :: OS Independent",
    ],
    install_requires=[
          'pandas', # it will install required packages which are used inside the programming
          'xlrd',
          'numpy',
          'pymongo',
          'pypyodbc',
          'pymysql',
          'boto3'
      ],
    python_requires='>=3.6',
)
``` 





command 

```
# go to the directory where setup.py present and execute
python3 setup.py install
``` 

After installation we can use this package anywhere we need like


```
from article import executor
executor.execute()
``` 

### Thanks ..