# Create a virtual environment in python


Suppose there is below script


```
➜  cat python2.py
print "anwer is :", 2+2

``` 

Installing Virtual Env:
```
pip install virtualenv --upgrade
```


Check version:
```
virtualenv --version
16.7.9
```

**Create environment:**

```
virtualenv python2_env
``` 
```
#Output of above command
python executable in /Users/siddartha/Desktop/delete/hashnodevm/python2_env/bin/python
Installing setuptools, pip, wheel...
done. 
```

This creates below directories
```
-python2_env
   ----bin
   ----include
   ----lib
```

use python2_env to use python2 as default 

```
which python2
/usr/bin/python2

#this creates python2 as default interpreter 
virtualenv -p /usr/bin/python2 python2_env

```

now the folder contains below

```
-python2_env
   ----bin
          ---- python2 --> python 
   ----include
   ----lib
```


**Activating Virtual Environments**
We will have (base) as our environment. In order to activate python2_env, use below:

```source python2_env/bin/activate```

So python environment gets modified to use python2 


List packages:
```
(python2_env) ➜   pip list

Package    Version
---------- -------
pip        20.3.4
setuptools 44.1.1
wheel      0.36.2
```


How to exit? 

```
deactivate
```

We now switch back to base environment 



**Configuring virtual environments**

Create a shell script as below 

```
cat run_python2_script.sh

source python2_env/bin/activate
python python2.py
deactivate
```

To execute shell script 
```
chmod +x run_python2_script.sh
./run_python2_script.sh
```




**SUMMARY**

```
#installing virtual environment
pip install virtualenv --upgrade

#Creating virtual environment
virtualenv python2_env

#Activating
source python2_env/bin/activate

#To check the library versions
pip list

#Deactivating
deactivate

```


How to create new virtual environments. Another method in latest python 
```python -m venv venvName```

This will create a new virtual environment called venvName in the current folder.

Additional information:

Found below link which is useful:
https://blog.teclado.com/python-virtual-environments-complete-guide/