[python-3.x] 'python3' is not recognized as an internal or external command, operable program or batch file

I am using Python 3.5.2 version on Windows 7 and tried using python3 app.py. I am getting this error message:

'python3' is not recognized as an internal or external command,
operable program or batch file. 

Is there any specific cause about why the python3 command is not working?

I also verified that the PATH is added to environment variables.

For Python 27

virtualenv -p C:\Python27\python.exe django_concurrent_env

For Pyton36

 virtualenv -p C:\Python36\python.exe django_concurrent_env

Yes, I think for Windows users you need to change all the python3 calls to python to solve your original error. This change will run the Python version set in your current environment. If you need to keep this call as it is (aka python3) because you are working in cross-platform or for any other reason, then a work around is to create a soft link. To create it, go to the folder that contains the Python executable and create the link. For example, this worked in my case in Windows 10 using mklink:

cd C:\Python3
mklink python3.exe python.exe

Use a (soft) symbolic link in Linux:

cd /usr/bin/python3
ln -s python.exe python3.exe

In my case I have a git hook on commit, specified by admin. So it was not very convenient for me to change the script (with python3 calls).

And the simplest workaround was just to copy python.exe to python3.exe.

Now I could launch both python and python3.

Python3.exe is not defined in windows

Specify the path for required version of python when you need to used it by creating virtual environment for your project

Python 3

virtualenv --python=C:\PATH_TO_PYTHON\python.exe environment

Python2

virtualenv --python=C:\PATH_TO_PYTHON\python.exe environment

then activate the environment using

.\environment\Scripts\activate.ps1

You can also try this: Go to the path where Python is installed in your system. For me it was something like C:\Users\\Local Settings\Application Data\Programs\Python\Python37 In this folder, you'll find a python executable. Just create a duplicate and rename it to python3. Works every time.

Enter the command to start up the server in that directory: py -3.7 -m http.server

If python2 is not installed on your computer, you can try with just python instead of python3