There are two ways to use the Python interpreter:
a) Interactive mode
b) Script mode
Interactive mode allows execution of individual statement instantaneously. Whereas, Script mode allows us to write more than one instruction in a file called Python source code file that can be executed.
(A) Interactive Mode
To work in the interactive mode, we can simply type a Python statement on the >>> prompt directly. As soon as we press enter, the interpreter executes the statement and displays the result(s), as shown in Figure.
Working in the interactive mode is convenient for testing a single line code for instant execution. But in the interactive mode, we cannot save the statements for future use and we have to retype the statements to run them again.
(B) Script Mode
In the script mode, we can write a Python program in a file, save it and then use the interpreter to execute it. Python scripts are saved as files where file name has extension “.py”. By default, the Python scripts are saved in the Python installation folder.
To execute a script, we can either:
a) Type the file name along with the path at the prompt. For example, if the name of the file is prog5-1.py, we type prog5-1.py. We can otherwise open the program directly from IDLE as shown in Figure.
b) While working in the script mode, after saving the file, click [Run]->[Run Module] from the menu as shown in Figure.
c) The output appears on shell as shown in Figure.
