The Python Apprentice

Conditional control flow: The if-statement

Conditional statements allow us to branch execution based on the value of an expression. The form of the statement is the if keyword, followed by an expression, terminated by a colon to introduce a new block. Let's try this at the REPL:

>>> if True:

Remembering to indent four spaces within the block, we add some code to be executed if the condition is True, followed by a blank line to terminate the block:

...     print("It's true!")...It's true!

At this point the block will execute, because self-evidently the condition is True. Conversely, if the condition is False, the code in the block does not execute:

>>> if False:...     print("It's true!")...>>>

The expression used with the if-statement will be converted ...