book

Python Cookbook, 2nd Edition

Name: Python Cookbook, 2nd Edition
ISBN: 9780596007973

by Alex Martelli, Anna Ravenscroft, David Ascher

March 2005

Intermediate to advanced

844 pages

25h 23m

English

O'Reilly Media, Inc.

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A Note Regarding Supplemental Files
Preface
The Design of the BookThe Implementation of the BookUsing the Code from This BookAudienceOrganizationFurther ReadingConventions Used in This BookHow to Contact UsSafari® EnabledAcknowledgments
1. Text
Introduction1.1. Processing a String One Character at a Time1.2. Converting Between Characters and Numeric Codes1.3. Testing Whether an Object Is String-like1.4. Aligning Strings1.5. Trimming Space from the Ends of a String1.6. Combining Strings1.7. Reversing a String by Words or Characters1.8. Checking Whether a String Contains a Set of Characters1.9. Simplifying Usage of Strings’ translate Method1.10. Filtering a String for a Set of Characters1.11. Checking Whether a String Is Text or Binary1.12. Controlling Case1.13. Accessing Substrings1.14. Changing the Indentation of a Multiline String1.15. Expanding and Compressing Tabs1.16. Interpolating Variables in a String1.17. Interpolating Variables in a Stringin Python 2.41.18. Replacing Multiple Patterns in a Single Pass1.19. Checking a String for Any of Multiple Endings1.20. Handling International Text with Unicode1.21. Converting Between Unicode and Plain Strings1.22. Printing Unicode Charactersto Standard Output1.23. Encoding Unicode Data for XML and HTML1.24. Making Some Strings Case-Insensitive1.25. Converting HTML Documents to Texton a Unix Terminal
2. Files
Introduction2.1. Reading from a File2.2. Writing to a File2.3. Searching and Replacing Text in a File2.4. Reading a Specific Line from a File2.5. Counting Lines in a File2.6. Processing Every Word in a File2.7. Using Random-Access Input/Output2.8. Updating a Random-Access File2.9. Reading Data from zip Files2.10. Handling a zip File Inside a String2.11. Archiving a Tree of Files into a Compressed tar File2.12. Sending Binary Data to Standard Output Under Windows2.13. Using a C++-like iostream Syntax2.14. Rewinding an Input File to the Beginning2.15. Adapting a File-like Object to a True File Object2.16. Walking Directory Trees2.17. Swapping One File Extension for Another Throughout a Directory Tree2.18. Finding a File Given a Search Path2.19. Finding Files Given a Search Path and a Pattern2.20. Finding a File on the Python Search Path2.21. Dynamically Changing the PythonSearch Path2.22. Computing the Relative Path from One Directory to Another2.23. Reading an Unbuffered Character in a Cross-Platform Way2.24. Counting Pages of PDF Documents on Mac OS X2.25. Changing File Attributes on Windows2.26. Extracting Text from OpenOffice.org Documents2.27. Extracting Text from Microsoft Word Documents2.28. File Locking Using a Cross-Platform API2.29. Versioning Filenames2.30. Calculating CRC-64 Cyclic Redundancy Checks
3. Time and Money
Introduction3.1. Calculating Yesterday and Tomorrow3.2. Finding Last Friday3.3. Calculating Time Periods in a Date Range3.4. Summing Durations of Songs3.5. Calculating the Number of Weekdays Between Two Dates3.6. Looking up Holidays Automatically3.7. Fuzzy Parsing of Dates3.8. Checking Whether Daylight Saving Time Is Currently in Effect3.9. Converting Time Zones3.10. Running a Command Repeatedly3.11. Scheduling Commands3.12. Doing Decimal Arithmetic3.13. Formatting Decimals as Currency3.14. Using Python as a Simple Adding Machine3.15. Checking a Credit Card Checksum3.16. Watching Foreign Exchange Rates
4. Python Shortcuts
Introduction4.1. Copying an Object4.2. Constructing Lists with List Comprehensions4.3. Returning an Element of a List If It Exists4.4. Looping over Items and Their Indices in a Sequence4.5. Creating Lists of Lists Without Sharing References4.6. Flattening a Nested Sequence4.7. Removing or Reordering Columnsin a List of Rows4.8. Transposing Two-Dimensional Arrays4.9. Getting a Value from a Dictionary4.10. Adding an Entry to a Dictionary4.11. Building a Dictionary Without Excessive Quoting4.12. Building a Dict from a List of Alternating Keys and Values4.13. Extracting a Subset of a Dictionary4.14. Inverting a Dictionary4.15. Associating Multiple Values with Each Key in a Dictionary4.16. Using a Dictionary to Dispatch Methods or Functions4.17. Finding Unions and Intersections of Dictionaries4.18. Collecting a Bunch of Named Items4.19. Assigning and Testing with One Statement4.20. Using printf in Python4.21. Randomly Picking Items with Given Probabilities4.22. Handling Exceptions Within an Expression4.23. Ensuring a Name Is Defined in a Given Module
5. Searching and Sorting
Introduction5.1. Sorting a Dictionary5.2. Sorting a List of Strings Case-Insensitively5.3. Sorting a List of Objects by an Attribute of the Objects5.4. Sorting Keys or Indices Basedon the Corresponding Values5.5. Sorting Strings with Embedded Numbers5.6. Processing All of a List’s Items in Random Order5.7. Keeping a Sequence Ordered as Items Are Added5.8. Getting the First Few Smallest Items of a Sequence5.9. Looking for Items in a Sorted Sequence5.10. Selecting the nth Smallest Element of a Sequence5.11. Showing off quicksort in Three Lines5.12. Performing Frequent Membership Tests on a Sequence5.13. Finding Subsequences5.14. Enriching the Dictionary Type with Ratings Functionality5.15. Sorting Names and Separating Them by Initials
6. Object-Oriented Programming
Introduction6.1. Converting Among Temperature Scales6.2. Defining Constants6.3. Restricting Attribute Setting6.4. Chaining Dictionary Lookups6.5. Delegating Automatically as an Alternative to Inheritance6.6. Delegating Special Methods in Proxies6.7. Implementing Tuples with Named Items6.8. Avoiding Boilerplate Accessors for Properties6.9. Making a Fast Copy of an Object6.10. Keeping References to Bound Methods Without Inhibiting Garbage Collection6.11. Implementing a Ring Buffer6.12. Checking an Instance for Any State Changes6.13. Checking Whether an Object Has Necessary Attributes6.14. Implementing the State Design Pattern6.15. Implementing the “Singleton” Design Pattern6.16. Avoiding the “Singleton” Design Pattern with the Borg Idiom6.17. Implementing the Null Object Design Pattern6.18. Automatically Initializing Instance Variables from _ _init_ _ Arguments6.19. Calling a Superclass _ _init_ _ Method If It Exists6.20. Using Cooperative Supercalls Concisely and Safely
7. Persistence and Databases
Introduction7.1. Serializing Data Using the marshal Module7.2. Serializing Data Using the pickle and cPickle Modules7.3. Using Compression with Pickling7.4. Using the cPickle Module on Classes and Instances7.5. Holding Bound Methods in a Picklable Way7.6. Pickling Code Objects7.7. Mutating Objects with shelve7.8. Using the Berkeley DB Database7.9. Accessing a MySQL Database7.10. Storing a BLOB in a MySQL Database7.11. Storing a BLOB in a PostgreSQL Database7.12. Storing a BLOB in a SQLite Database7.13. Generating a Dictionary Mapping Field Names to Column Numbers7.14. Using dtuple for Flexible Accessto Query Results7.15. Pretty-Printing the Contents of Database Cursors7.16. Using a Single Parameter-Passing Style Across Various DB API Modules7.17. Using Microsoft Jet via ADO7.18. Accessing a JDBC Database from a Jython Servlet7.19. Using ODBC to Get Excel Data with Jython
8. Debugging and Testing
Introduction8.1. Disabling Execution of Some Conditionals and Loops8.2. Measuring Memory Usage on Linux8.3. Debugging the Garbage-Collection Process8.4. Trapping and Recording Exceptions8.5. Tracing Expressions and Comments in Debug Mode8.6. Getting More Information from Tracebacks8.7. Starting the Debugger Automatically After an Uncaught Exception8.8. Running Unit Tests Most Simply8.9. Running Unit Tests Automatically8.10. Using doctest with unittest in Python 2.48.11. Checking Values Against Intervals in Unit Testing

9. Processes, Threads, and Synchronization
Introduction9.1. Synchronizing All Methods in an Object9.2. Terminating a Thread9.3. Using a Queue.Queue as a Priority Queue9.4. Working with a Thread Pool9.5. Executing a Function in Parallel on Multiple Argument Sets9.6. Coordinating Threads by Simple Message Passing9.7. Storing Per-Thread Information9.8. Multitasking Cooperatively Without Threads9.9. Determining Whether Another Instanceof a Script Is Already Running in Windows9.10. Processing Windows Messages Using MsgWaitForMultipleObjects9.11. Driving an External Process with popen9.12. Capturing the Output and Error Streams from a Unix Shell Command9.13. Forking a Daemon Process on Unix
10. System Administration
Introduction10.1. Generating Random Passwords10.2. Generating Easily Remembered Somewhat-Random Passwords10.3. Authenticating Users by Means of a POP Server10.4. Calculating Apache Hits per IP Address10.5. Calculating the Rate of Client Cache Hits on Apache10.6. Spawning an Editor from a Script10.7. Backing Up Files10.8. Selectively Copying a Mailbox File10.9. Building a Whitelist of Email Addresses From a Mailbox10.10. Blocking Duplicate Mails10.11. Checking Your Windows Sound System10.12. Registering or Unregistering a DLL on Windows10.13. Checking and Modifying the Set of Tasks Windows Automatically Runs at Login10.14. Creating a Share on Windows10.15. Connecting to an Already Running Instance of Internet Explorer10.16. Reading Microsoft Outlook Contacts10.17. Gathering Detailed System Informationon Mac OS X
11. User Interfaces
Introduction11.1. Showing a Progress Indicator on a Text Console11.2. Avoiding lambda in Writing Callback Functions11.3. Using Default Values and Bounds with tkSimpleDialog Functions11.4. Adding Drag and Drop Reordering to a Tkinter Listbox11.5. Entering Accented Characters in Tkinter Widgets11.6. Embedding Inline GIFs Using Tkinter11.7. Converting Among Image Formats11.8. Implementing a Stopwatch in Tkinter11.9. Combining GUIs and Asynchronous I/Owith Threads11.10. Using IDLE’s Tree Widget in Tkinter11.11. Supporting Multiple Values per Row in a Tkinter Listbox11.12. Copying Geometry Methods and Options Between Tkinter Widgets11.13. Implementing a Tabbed Notebook for Tkinter11.14. Using a wxPython Notebook with Panels11.15. Implementing an ImageJ Plug-in in Jython11.16. Viewing an Image from a URL with Swing and Jython11.17. Getting User Input on Mac OS11.18. Building a Python Cocoa GUI Programmatically11.19. Implementing Fade-in Windows with IronPython
12. Processing XML
Introduction12.1. Checking XML Well-Formedness12.2. Counting Tags in a Document12.3. Extracting Text from an XML Document12.4. Autodetecting XML Encoding12.5. Converting an XML Document into a Tree of Python Objects12.6. Removing Whitespace-only Text Nodes from an XML DOM Node’s Subtree12.7. Parsing Microsoft Excel’s XML12.8. Validating XML Documents12.9. Filtering Elements and Attributes Belonging to a Given Namespace12.10. Merging Continuous Text Events with a SAX Filter12.11. Using MSHTML to Parse XML or HTML
13. Network Programming
Introduction13.1. Passing Messages with Socket Datagrams13.2. Grabbing a Document from the Web13.3. Filtering a List of FTP Sites13.4. Getting Time from a Server via the SNTP Protocol13.5. Sending HTML Mail13.6. Bundling Files in a MIME Message13.7. Unpacking a Multipart MIME Message13.8. Removing Attachments from an Email Message13.9. Fixing Messages Parsed by Python 2.4 email.FeedParser13.10. Inspecting a POP3 Mailbox Interactively13.11. Detecting Inactive Computers13.12. Monitoring a Network with HTTP13.13. Forwarding and Redirecting Network Ports13.14. Tunneling SSL Through a Proxy13.15. Implementing the Dynamic IP Protocol13.16. Connecting to IRC and Logging Messages to Disk13.17. Accessing LDAP Servers
14. Web Programming
Introduction14.1. Testing Whether CGI Is Working14.2. Handling URLs Within a CGI Script14.3. Uploading Files with CGI14.4. Checking for a Web Page’s Existence14.5. Checking Content Type via HTTP14.6. Resuming the HTTP Download of a File14.7. Handling Cookies While Fetching Web Pages14.8. Authenticating with a Proxy for HTTPS Navigation14.9. Running a Servlet with Jython14.10. Finding an Internet Explorer Cookie14.11. Generating OPML Files14.12. Aggregating RSS Feeds14.13. Turning Data into Web Pages Through Templates14.14. Rendering Arbitrary Objects with Nevow
15. Distributed Programming
Introduction15.1. Making an XML-RPC Method Call15.2. Serving XML-RPC Requests15.3. Using XML-RPC with Medusa15.4. Enabling an XML-RPC Server to Be Terminated Remotely15.5. Implementing SimpleXMLRPCServer Niceties15.6. Giving an XML-RPC Server a wxPython GUI15.7. Using Twisted Perspective Broker15.8. Implementing a CORBA Server and Client15.9. Performing Remote Logins Using telnetlib15.10. Performing Remote Logins with SSH15.11. Authenticating an SSL Client over HTTPS
16. Programs About Programs
Introduction16.1. Verifying Whether a String Represents a Valid Number16.2. Importing a Dynamically Generated Module16.3. Importing from a Module Whose Name Is Determined at Runtime16.4. Associating Parameters with a Function (Currying)16.5. Composing Functions16.6. Colorizing Python Source Using the Built-in Tokenizer16.7. Merging and Splitting Tokens16.8. Checking Whether a String Has Balanced Parentheses16.9. Simulating Enumerations in Python16.10. Referring to a List Comprehension While Building It16.11. Automating the py2exe Compilation of Scripts into Windows Executables16.12. Binding Main Script and Modules into One Executable on Unix
17. Extending and Embedding
Introduction17.1. Implementing a Simple Extension Type17.2. Implementing a Simple Extension Type with Pyrex17.3. Exposing a C++ Library to Python17.4. Calling Functions from a Windows DLL17.5. Using SWIG-Generated Modules in a Multithreaded Environment17.6. Translating a Python Sequence into a C Array with the PySequence_Fast Protocol17.7. Accessing a Python Sequence Item-by-Item with the Iterator Protocol17.8. Returning None from a Python-Callable C Function17.9. Debugging Dynamically Loaded C Extensions with gdb17.10. Debugging Memory Problems
18. Algorithms
Introduction18.1. Removing Duplicates from a Sequence18.2. Removing Duplicates from a Sequence While Maintaining Sequence Order18.3. Generating Random Samples with Replacement18.4. Generating Random Samples Without Replacement18.5. Memoizing (Caching) the Return Values of Functions18.6. Implementing a FIFO Container18.7. Caching Objects with a FIFO Pruning Strategy18.8. Implementing a Bag (Multiset) Collection Type18.9. Simulating the Ternary Operator in Python18.10. Computing Prime Numbers18.11. Formatting Integers as Binary Strings18.12. Formatting Integers as Strings in Arbitrary Bases18.13. Converting Numbers to Rationals via Farey Fractions18.14. Doing Arithmetic with Error Propagation18.15. Summing Numbers with Maximal Accuracy18.16. Simulating Floating Point18.17. Computing the Convex Hulls and Diameters of 2D Point Sets
19. Iterators and Generators
Introduction19.1. Writing a range-like Function with Float Increments19.2. Building a List from Any Iterable19.3. Generating the Fibonacci Sequence19.4. Unpacking a Few Items in a Multiple Assignment19.5. Automatically Unpacking the Needed Number of Items19.6. Dividing an Iterable into n Slices of Stride n19.7. Looping on a Sequence by Overlapping Windows19.8. Looping Through Multiple Iterables in Parallel19.9. Looping Through the Cross-Product of Multiple Iterables19.10. Reading a Text File by Paragraphs19.11. Reading Lines with Continuation Characters19.12. Iterating on a Stream of Data Blocks as a Stream of Lines19.13. Fetching Large Record Sets from a Database with a Generator19.14. Merging Sorted Sequences19.15. Generating Permutations, Combinations, and Selections19.16. Generating the Partitions of an Integer19.17. Duplicating an Iterator19.18. Looking Ahead into an Iterator19.19. Simplifying Queue-Consumer Threads19.20. Running an Iterator in Another Thread19.21. Computing a Summary Report with itertools.groupby
20. Descriptors, Decorators,and Metaclasses
Introduction20.1. Getting Fresh Default Values at Each Function Call20.2. Coding Properties as Nested Functions20.3. Aliasing Attribute Values20.4. Caching Attribute Values20.5. Using One Method as Accessorfor Multiple Attributes20.6. Adding Functionality to a Class by Wrapping a Method20.7. Adding Functionality to a Class by Enriching All Methods20.8. Adding a Method to a Class Instance at Runtime20.9. Checking Whether Interfaces Are Implemented20.10. Using _ _new_ _ and _ _init_ _ Appropriately in Custom Metaclasses20.11. Allowing Chaining of Mutating List Methods20.12. Using Cooperative Super calls with Terser Syntax20.13. Initializing Instance Attributes Without Using _ _init_ _20.14. Automatic Initialization of Instance Attributes20.15. Upgrading Class Instances Automatically on reload20.16. Binding Constants at Compile Time20.17. Solving Metaclass Conflicts
Index
About the Authors
Colophon
Copyright

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Python Cookbook, 2nd Edition

by Alex Martelli, Anna Ravenscroft, David Ascher

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