2.11. if StatementThe standard if conditional statement follows this syntax: if expression: if_suite If the expression is non-zero or TRue, then the statement if_suite is executed; otherwise, execution continues on the first statement after. Suite is the term used in Python to refer to a sub-block of code and can consist of single or multiple statements. You will notice that parentheses are not required in if statements as they are in other languages. if x < .0: print '"x" must be atleast 0!' Python supports an else statement that is used with if in the following manner: if expression: if_suite else: else_suite Python has an "else-if" spelled as elif with the following syntax: if expression1: if_suite elif expression2: elif_suite else: else_suite At the time of this writing, there has been some discussion pertaining to a switch or case statement, but nothing concrete. It is possible that we will see such an animal in a future version of the language. This may also seem strange and/or distracting at first, but a set of if-elif-else statements are not as "ugly" because of Python's clean syntax. If you really want to circumvent a set of chained if-elif-else statements, another elegant workaround is using a for loop (see Section 2.13) to iterate through your list of possible "cases." You can learn more about if, elif, and else statements in the conditional section of Chapter 8. |