IDLE is Python’s Integrated Development and Learning Environment and is an alternative to the command line. As the name may imply, IDLE is very useful for developing new code or learning python. On Windows this comes with the Python interpreter, but in other operating systems you may need to install it through your package manager.
The main purposes of IDLE are:
In IDLE, hit F5
or run Python Shell
to launch an interpreter. Using IDLE can be a better learning experience for new users because code is interpreted as the user writes.
Note that there are lots of alternatives, see for example this discussion or this list.
Windows
If you're on Windows, the default command is python
. If you receive a "'python' is not recognized"
error, the most likely cause is that Python's location is not in your system's PATH
environment variable. This can be accessed by right-clicking on 'My Computer' and selecting 'Properties' or by navigating to 'System' through 'Control Panel'. Click on 'Advanced system settings' and then 'Environment Variables...'. Edit the PATH
variable to include the directory of your Python installation, as well as the Script folder (usually C:\Python27;C:\Python27\Scripts
). This requires administrative privileges and may require a restart.
When using multiple versions of Python on the same machine, a possible solution is to rename one of the python.exe
files. For example, naming one version python27.exe
would cause python27
to become the Python command for that version.
You can also use the Python Launcher for Windows, which is available through the installer and comes by default. It allows you to select the version of Python to run by using py -[x.y]
instead of python[x.y]
. You can use the latest version of Python 2 by running scripts with py -2
and the latest version of Python 3 by running scripts with py -3
.
Debian/Ubuntu/MacOS
This section assumes that the location of the python
executable has been added to the PATH
environment variable.
If you're on Debian/Ubuntu/MacOS, open the terminal and type python
for Python 2.x or python3
for Python 3.x.
Type which python
to see which Python interpreter will be used.
Arch Linux
The default Python on Arch Linux (and descendants) is Python 3, so use python
or python3
for Python 3.x and python2
for Python 2.x.
Other systems
Python 3 is sometimes bound to python
instead of python3
. To use Python 2 on these systems where it is installed, you can use python2
.