#Starting Python Web development in Mac OS X#

**Objective:** Getting started with Python Development
**Operating System:** Mac OS X
**Python version installed:** 3.5 (5th December 2015)


Downoad the lastest Python from https://www.python.org/downloads/

Mac OS uses default 2.x version out of box.
To check whether, python has been installed successfully. try the following command.

    python3 -V
    Python 3.5.0

Above step ensure that Python 3.5 has been installed successfully.

This is the high level outline of this post:
Mas OS X -> Python 3.5 -> Virtaulenv -> Flask --> app.py(first Hello world )


Installing virtaulenv: (Step 1 of 
Why use virtualenv?
1. Having different version of libraries for different projects
2. Solves the elevated privillege issue as virtualenv allows you to install with user permission
```bash
    sudo pip3 install virtualenv
    virtualenv --version
    13.1.2
```  
Now lets create the first flask app
```shell
mkdir ~/projects
    cd ~/projects
```

Now we will create a virtualenv
```shell
virtualenv hello_flask
cd hello_flask
```

If you list the contents of the hello_flask directory, you will see that it has created several sub-directories, including a bin folder (Scripts on Windows) that contains copies of both Python and pip. The next step is to activate your new virtualenv.
```shell
source bin/activate
```

Installing Flask in your virtaulenv

    pip install Flask

Hello, Flask

Create a new file called app.py
```python
from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
	return 'Hello, Flask!'

if __name__ == '__main__':
	app.run(debug=True)

````
Open the web browser with ```http://localhost:5000```