standardize virtualenv for python instructions

inspired by https://azure.microsoft.com/en-ca/resources/samples/virtual-machines-python-manage/ -- we could do this for https://github.com/IBM/MAX-Facial-Age-Estimator-Web-App and the Watson Online Store.

README.md

@@ -67,7 +67,7 @@ Follow these steps to setup and run this code pattern. The steps are
 described in detail below.
 
 1. [Clone the repo](#1-clone-the-repo)
-2. [Install Prerequisites](#2-install-prerequisites)
+2. [Install dependencies](#2-install-dependencies)
 3. [Generate Image Data](#3-generate-image-data)
 4. [Convert Images to TFRecords](#4-convert-images-to-tfrecords)
 5. [Train the Model](#5-train-the-model)
@@ -82,30 +82,34 @@ Clone the `tensorflow-hangul-recognition` locally. In a terminal, run:
 git clone https://github.com/IBM/tensorflow-hangul-recognition
 ```
 
-### 2. Install Prerequisites
+### 2. Install dependencies
 
-Go to your cloned repo directory:
-```
-cd tensorflow-hangul-recognition
+The general recommendation for Python development is to use a virtual environment [(venv)](https://docs.python.org/3/tutorial/venv.html). To install and initialize a virtual environment, use the `venv` module on Python 3 (you install the virtualenv library for Python 2.7):
+
+```bash
+# Create the virtual environment using Python. Use one of the two commands depending on your Python version.
+# Note, it may be named python3 on your system.
+
+$ python -m venv mytestenv       # Python 3.X
+$ virtualenv mytestenv           # Python 2.X
+
+# Now source the virtual environment. Use one of the two commands depending on your OS.
+
+$ source mytestenv/bin/activate  # Mac or Linux
+$ ./mytestenv/Scripts/activate   # Windows PowerShell
 ```
 
-Optionally, to isolate your runtime environment, use a virtual environment as described
-[here](https://packaging.python.org/guides/installing-using-pip-and-virtualenv/).
-Create a virtual environment:
+Now go to the cloned repo directory:
 ```
-python -m pip install --user virtualenv
-python -m virtualenv .venv
+cd tensorflow-hangul-recognition
 ```
 
-Then activate the virtual environment with `source .venv/bin/activate` on Linux/macOS or
-`.venv\Scripts\activate` on Windows.
-
-Install the python requirements for this code pattern. Run:
+Install the Python requirements for this code pattern. Run:
 ```
 pip install -r requirements.txt
 ```
 
-When you have completed the code pattern, use the `deactivate` command to leave the virtual environment.
+> **TIP** :bulb: To terminate the virtual environment use the `deactivate` command.
 
 **Note:** For Windows users, the _scipy_ package is not installable via **pip**.
 The recommended way to use _scipy_ is to install a
@@ -434,4 +438,4 @@ writing.
 
 This code pattern is licensed under the Apache Software License, Version 2.  Separate third party code objects invoked within this code pattern are licensed by their respective providers pursuant to their own separate licenses. Contributions are subject to the [Developer Certificate of Origin, Version 1.1 (DCO)](https://developercertificate.org/) and the [Apache Software License, Version 2](http://www.apache.org/licenses/LICENSE-2.0.txt).
 
-[Apache Software License (ASL) FAQ](http://www.apache.org/foundation/license-faq.html#WhatDoesItMEAN)
+[Apache Software License (ASL) FAQ](http://www.apache.org/foundation/license-faq.html#WhatDoesItMEAN)