Last updated: Friday 31st October
2008 (Boo!), 7:06 PT by AHD
How to run the Python interpreter
Introduction
After installing
the Python software, the Python interpreter is ready to run single Python
commands like:
print "Hello World!"
The CSCI120A Course Notes and the
CSCI165A Course Notes web
pages contain instructions for the use of various editors which allow you to
store several Python statements in one file to be executed in sequence by the
Python interpreter.
Running the Python interpreter
Please note: the screen shots shown
are generated from a computer running the Windows 98 operating system. If you
have another version of Windows the screens may look slightly different, but
the procedures you should follow are the same.
You can run the Python interpreter
in a number of ways:
Running Python - Method 1
On your desktop, click on the Start button, then
click on Run .
Assuming you installed the Python
software to the folder:
C:\Python23
In the Run window, enter the following
text in the text box, then click on the OK button.
C:\Python23\python.exe
You will then see Python running in
an MSDOS window (DOS shell):
You will see a few lines of
information followed by the Python prompt >>>. A prompt is simply the
location where instructions are typed in (at the shell command line).
After typing in a Python statement
at the prompt, you must press the Enter key (also known as the Return key) on
your keyboard.
At the >>> prompt, try
typing in the following simple Python statement:
print "Hello
World!" (then press the Enter key).
Python responds by printing the text
"Hello World!" (without the quotes).
If you've got this far, you know
that Python has been installed correctly!
Notice that after Python interprets
and executes your command, the prompt returns ready for the next command
(Python statement). When running in this manner the Python interpreter is said
to be in the interactive mode, and will continue in this mode indefinitely
until you issue the command to quit.
To exit from the Python interpreter
you must hold down the Ctrl keyboard key and press the Z key at the same time
(Ctrl-Z). (Different operating systems may require a different key sequence,
e.g. Ctrl-C).
Running Python - Method 2
On your desktop, click on the Start button, then
click on Programs , then Python
2.3.4 , then select Python (command line) from the list of options.
Notice that the Python interpreter is
running in exactly the same DOS shell as shown in Method 1 above. You may
follow the same instructions for using the interpreter as described for Method
1.
Running Python - Method 3
In the third method of running the python
interpreter, you execute the interpreter by typing its file name at an MSDOS
shell command line. From the desktop, click on the Start button, then
click on Programs , then MS-DOS
Prompt . (In other versions of Windows, the MS-DOS
prompt may have an alternative name, eg DOS Shell, Command shell, etc.)
Please note, other operating systems
may default to a different folder than C:\WINDOWS. Notice that the prompt for
MS-DOS is a single right arrow symbol >. The prompt for the Python interpreter
is >>>.
Then type in the following text at
the MS-DOS prompt, and press the Enter key to run the Python interpreter:
c:\python23\python.exe
The screen above shows the Python
interpreter running in interactive mode. See Running Python - Method 1
for an explanation of interactive mode and instructions on the use of the
Python interpreter with single Python commands. As explained earlier, to exit
from the Python interpreter you must hold down the Ctrl keyboard key and
press the Z key at the same time. (Operating systems other than Windows
may require a different key sequence, e.g. Ctrl-C).
If you run Python from an MS-DOS
Prompt shell, exiting from Python returns you to the MS-DOS Prompt shell. To
close the DOS shell and return to Windows, you must exit the MS-DOS Prompt
environment by typing exit at the command prompt, then press the Enter key. An example of this is
shown in the screen below.
