␡
- 2.1 Program Output, the print Statement, and Hello World!
- 2.2 Program Input and the raw_input()Built-in Function
- 2.3 Comments
- 2.4 Operators
- 2.5 Variables and Assignment
- 2.6 Numbers
- 2.7 Strings
- 2.8 Lists and Tuples
- 2.9 Dictionaries
- 2.10 Code Blocks Use Indentation
- 2.11 if Statement
- 2.12 while Loop
- 2.13 for Loop and the range() Built-in Function
- 2.14 List Comprehensions
- 2.15 Files and the open() and file() Built-in Functions
- 2.16 Errors and Exceptions
- 2.17 Functions
- 2.18 Classes
- 2.19 Modules
- 2.20 Useful Functions
- 2.21 Exercises
This chapter is from the book
This chapter is from the book
This chapter is from the book
This chapter is from the book
2.12 while Loop
The standard while conditional loop statement is similar to the if. Again, as with every code sub-block, indentation (and dedentation) are used to delimit blocks of code as well as to indicate which block of code statements belong to:
while expression:
while_suite
The statement while_suite is executed continuously in a loop until the expression becomes zero or false; execution then continues on the first succeeding statement. Like if statements, parentheses are not required with Python while statements.
>>> counter = 0 >>> while counter < 3: ... print 'loop #%d' % (counter) ... counter += 1 loop #0 loop #1 loop #2
Loops such as while and for (see below) are covered in the loops section of Chapter 8.