Python Cookbook, 2/e (Paperback)

Description:

Portable, powerful, and a breeze to use, Python is the popular open source object-oriented programming language used for both standalone programs and scripting applications. It is now being used by an increasing number of major organizations, including NASA and Google.

Updated for Python 2.4, The Python Cookbook, 2nd Edition offers a wealth of useful code for all Python programmers, not just advanced practitioners. Like its predecessor, the new edition provides solutions to problems that Python programmers face everyday.

It now includes over 200 recipes that range from simple tasks, such as working with dictionaries and list comprehensions, to complex tasks, such as monitoring a network and building a templating system. This revised version also includes new chapters on topics such as time, money, and metaprogramming.

Here's a list of additional topics covered:

• Manipulating text
  
• Searching and sorting
  
• Working with files and the filesystem
  
• Object-oriented programming
  
• Dealing with threads and processes
  
• System administration
  
• Interacting with databases
  
• Creating user interfaces
  
• Network and web programming
  
• Processing XML
  
• Distributed programming
  
• Debugging and testing

Another advantage of The Python Cookbook, 2nd Edition is its trio of authors--three well-known Python programming experts, who are highly visible on email lists and in newsgroups, and speak often at Python conferences.

With scores of practical examples and pertinent background information, The Python Cookbook, 2nd Edition is the one source you need if you're looking to build efficient, flexible, scalable, and well-integrated systems.

 

 

Table of Contents:

Preface

1. Text

      1.1 Processing a String One Character at a Time  

      1.2 Converting Between Characters and Numeric Codes  

      1.3 Testing Whether an Object Is String-like  

      1.4 Aligning Strings  

      1.5 Trimming Space from the Ends of a String  

      1.6 Combining Strings  

      1.7 Reversing a String by Words or Characters  

      1.8 Checking Whether a String Contains a Set of Characters  

      1.9 Simplifying Usage of Strings' translate Method  

      1.10 Filtering a String for a Set of Characters  

      1.11 Checking Whether a String Is Text or Binary  

      1.12 Controlling Case  

      1.13 Accessing Substrings  

      1.14 Changing the Indentation of a Multiline String  

      1.15 Expanding and Compressing Tabs  

      1.16 Interpolating Variables in a String  

      1.17 Interpolating Variables in a String in Python 2.4  

      1.18 Replacing Multiple Patterns in a Single Pass  

      1.19 Checking a String for Any of Multiple Endings  

      1.20 Handling International Text with Unicode  

      1.21 Converting Between Unicode and Plain Strings  

      1.22 Printing Unicode Characters to Standard Output  

      1.23 Encoding Unicode Data for XML and HTML  

      1.24 Making Some Strings Case-Insensitive  

      1.25 Converting HTML Documents to Text on a Unix Terminal  

2. Files

      2.1 Reading from a File  

      2.2 Writing to a File  

      2.3 Searching and Replacing Text in a File  

      2.4 Reading a Specific Line from a File  

      2.5 Counting Lines in a File  

      2.6 Processing Every Word in a File  

      2.7 Using Random-Access Input/Output  

      2.8 Updating a Random-Access File  

      2.9 Reading Data from zip Files  

      2.10 Handling a zip File Inside a String  

      2.11 Archiving a Tree of Files into a Compressed tar File  

      2.12 Sending Binary Data to Standard Output Under Windows  

      2.13 Using a C++-like iostream Syntax  

      2.14 Rewinding an Input File to the Beginning  

      2.15 Adapting a File-like Object to a True File Object  

      2.16 Walking Directory Trees  

      2.17 Swapping One File Extension for AnotherThroughout a Directory Tree  

      2.18 Finding a File Given a Search Path  

      2.19 Finding Files Given a Search Path and a Pattern  

      2.20 Finding a File on the Python Search Path  

      2.21 Dynamically Changing the Python Search Path  

      2.22 Computing the Relative Path from One Directory to Another  

      2.23 Reading an Unbuffered Character in a Cross-Platform Way  

      2.24 Counting Pages of PDF Documents on Mac OS X  

      2.25 Changing File Attributes on Windows  

      2.26 Extracting Text from OpenOffice.org Documents  

      2.27 Extracting Text from Microsoft Word Documents  

      2.28 File Locking Using a Cross-Platform API  

      2.29 Versioning Filenames  

      2.30 Calculating CRC-64 Cyclic Redundancy Checks  

3. Time and Money

      3.1 Calculating Yesterday and Tomorrow  

      3.2 Finding Last Friday  

      3.3 Calculating Time Periods in a Date Range  

      3.4 Summing Durations of Songs  

      3.5 Calculating the Number of Weekdays Between Two Dates  

      3.6 Looking up Holidays Automatically  

      3.7 Fuzzy Parsing of Dates  

      3.8 Checking Whether Daylight Saving Time Is Currently in Effect  

      3.9 Converting Time Zones  

      3.10 Running a Command Repeatedly  

      3.11 Scheduling Commands  

      3.12 Doing Decimal Arithmetic  

      3.13 Formatting Decimals as Currency  

      3.14 Using Python as a Simple Adding Machine  

      3.15 Checking a Credit Card Checksum  

      3.16 Watching Foreign Exchange Rates  

4. Python Shortcuts

      4.1 Copying an Object  

      4.2 Constructing Lists with List Comprehensions  

      4.3 Returning an Element of a List If It Exists  

      4.4 Looping over Items and Their Indices in a Sequence  

      4.5 Creating Lists of Lists Without Sharing References  

      4.6 Flattening a Nested Sequence  

      4.7 Removing or Reordering Columns in a List of Rows  

      4.8 Transposing Two-Dimensional Arrays  

      4.9 Getting a Value from a Dictionary  

      4.10 Adding an Entry to a Dictionary  

      4.11 Building a Dictionary Without Excessive Quoting  

      4.12 Building a Dict from a List of Alternating Keys and Values  

      4.13 Extracting a Subset of a Dictionary  

      4.14 Inverting a Dictionary  

      4.15 Associating Multiple Values with Each Key in a Dictionary  

      4.16 Using a Dictionary to Dispatch Methods or Functions  

      4.17 Finding Unions and Intersections of Dictionaries  

      4.18 Collecting a Bunch of Named Items  

      4.19 Assigning and Testing with One Statement  

      4.20 Using printf in Python  

      4.21 Randomly Picking Items with Given Probabilities  

      4.22 Handling Exceptions Within an Expression  

      4.23 Ensuring a Name Is Defined in a Given Module  

5. Searching and Sorting

      5.1 Sorting a Dictionary  

      5.2 Sorting a List of Strings Case-Insensitively  

      5.3 Sorting a List of Objects by an Attribute of the Objects  

      5.4 Sorting Keys or Indices Based on the Corresponding Values  

      5.5 Sorting Strings with Embedded Numbers  

      5.6 Processing All of a List's Items in Random Order  

      5.7 Keeping a Sequence Ordered as Items Are Added  

      5.8 Getting the First Few Smallest Items of a Sequence  

      5.9 Looking for Items in a Sorted Sequence  

      5.10 Selecting the nth Smallest Element of a Sequence  

      5.11 Showing off quicksort in Three Lines  

      5.12 Performing Frequent Membership Tests on a Sequence  

      5.13 Finding Subsequences  

      5.14 Enriching the Dictionary Type with Ratings Functionality  

      5.15 Sorting Names and Separating Them by Initials  

6. Object-Oriented Programming

      6.1 Converting Among Temperature Scales  

      6.2 Defining Constants  

      6.3 Restricting Attribute Setting  

      6.4 Chaining Dictionary Lookups  

      6.5 Delegating Automatically as an Alternative to Inheritance  

      6.6 Delegating Special Methods in Proxies  

      6.7 Implementing Tuples with Named Items  

      6.8 Avoiding Boilerplate Accessors for Properties  

      6.9 Making a Fast Copy of an Object  

      6.10 Keeping References to Bound MethodsWithout Inhibiting Garbage Collection  

      6.11 Implementing a Ring Buffer  

      6.12 Checking an Instance for Any State Changes  

      6.13 Checking Whether an Object Has Necessary Attributes  

      6.14 Implementing the State Design Pattern  

      6.15 Implementing the "Singleton" Design Pattern  

      6.16 Avoiding the "Singleton" Design Pattern with the Borg Idiom  

      6.17 Implementing the Null Object Design Pattern  

      6.18 Automatically Initializing Instance Variablesfrom _ _init_ _ Arguments  

      6.19 Calling a Superclass _ _init_ _ Method If It Exists  

      6.20 Using Cooperative Supercalls Concisely and Safely  

7. Persistence and Databases

      7.1 Serializing Data Using the marshal Module  

      7.2 Serializing Data Using the pickle and cPickle Modules  

      7.3 Using Compression with Pickling  

      7.4 Using the cPickle Module on Classes and Instances  

      7.5 Holding Bound Methods in a Picklable Way  

      7.6 Pickling Code Objects  

      7.7 Mutating Objects with shelve  

      7.8 Using the Berkeley DB Database  

      7.9 Accesssing a MySQL Database  

      7.10 Storing a BLOB in a MySQL Database  

      7.11 Storing a BLOB in a PostgreSQL Database  

      7.12 Storing a BLOB in a SQLite Database  

      7.13 Generating a Dictionary Mapping Field Names to Column Numbers  

      7.14 Using dtuple for Flexible Accessto Query Results  

      7.15 Pretty-Printing the Contents of Database Cursors  

      7.16 Using a Single Parameter-Passing StyleAcross Various DB API Modules  

      7.17 Using Microsoft Jet via ADO  

      7.18 Accessing a JDBC Database from a Jython Servlet  

      7.19 Using ODBC to Get Excel Data with Jython  

8. Debugging and Testing

      8.1 Disabling Execution of Some Conditionals and Loops  

      8.2 Measuring Memory Usage on Linux  

      8.3 Debugging the Garbage-Collection Process  

      8.4 Trapping and Recording Exceptions  

      8.5 Tracing Expressions and Comments in Debug Mode  

      8.6 Getting More Information from Tracebacks  

      8.7 Starting the Debugger Automatically After an Uncaught Exception  

      8.8 Running Unit Tests Most Simply  

      8.9 Running Unit Tests Automatically  

      8.10 Using doctest with unittest in Python 2.4  

      8.11 Checking Values Against Intervals in Unit Testing  

9. Processes, Threads, and Synchronization

      9.1 Synchronizing All Methods in an Object  

      9.2 Terminating a Thread  

      9.3 Using a Queue.Queue as a Priority Queue  

      9.4 Working with a Thread Pool  

      9.5 Executing a Function in Parallel on Multiple Argument Sets  

      9.6 Coordinating Threads by Simple Message Passing  

      9.7 Storing Per-Thread Information  

      9.8 Multitasking Cooperatively Without Threads  

      9.9 Determining Whether Another Instance of a ScriptIs Already Running in Windows  

      9.10 Processing Windows Messages Using MsgWaitForMultipleObjects  

      9.11 Driving an External Process with popen  

      9.12 Capturing the Output and Error Streamsfrom a Unix Shell Command  

      9.13 Forking a Daemon Process on Unix  

10. System Administration

      10.1 Generating Random Passwords  

      10.2 Generating Easily Remembered Somewhat-Random Passwords  

      10.3 Authenticating Users by Means of a POP Server  

      10.4 Calculating Apache Hits per IP Address  

      10.5 Calculating the Rate of Client Cache Hits on Apache  

      10.6 Spawning an Editor from a Script  

      10.7 Backing Up Files  

      10.8 Selectively Copying a Mailbox File  

      10.9 Building a Whitelist of Email Addresses From a Mailbox  

      10.10 Blocking Duplicate Mails  

      10.11 Checking Your Windows Sound System  

      10.12 Registering or Unregistering a DLL on Windows  

      10.13 Checking and Modifying the Set of Tasks WindowsAutomatically Runs at Login  

      10.14 Creating a Share on Windows  

      10.15 Connecting to an Already Running Instance of Internet Explorer  

      10.16 Reading Microsoft Outlook Contacts  

      10.17 Gathering Detailed System Information on Mac OS X  

11. User Interfaces

      11.1 Showing a Progress Indicator on a Text Console  

      11.2 Avoiding lambda in Writing Callback Functions  

      11.3 Using Default Values and Bounds with tkSimpleDialog Functions  

      11.4 Adding Drag and Drop Reordering to a Tkinter Listbox  

      11.5 Entering Accented Characters in Tkinter Widgets  

      11.6 Embedding Inline GIFs Using Tkinter  

      11.7 Converting Among Image Formats  

      11.8 Implementing a Stopwatch in Tkinter  

      11.9 Combining GUIs and Asynchronous I/O with Threads  

      11.10 Using IDLE's Tree Widget in Tkinter  

      11.11 Supporting Multiple Values per Row in a Tkinter Listbox  

      11.12 Copying Geometry Methods and Options Between Tkinter Widgets  

      11.13 Implementing a Tabbed Notebook for Tkinter  

      11.14 Using a wxPython Notebook with Panels  

      11.15 Implementing an ImageJ Plug-in in Jython  

      11.16 Viewing an Image from a URL with Swing and Jython  

      11.17 Getting User Input on Mac OS  

      11.18 Building a Python Cocoa GUI Programmatically  

      11.19 Implementing Fade-in Windows with IronPython  

12. Processing XML

      12.1 Checking XML Well-Formedness  

      12.2 Counting Tags in a Document  

      12.3 Extracting Text from an XML Document  

      12.4 Autodetecting XML Encoding  

      12.5 Converting an XML Document into a Tree of Python Objects  

      12.6 Removing Whitespace-only Text Nodesfrom an XML DOM Node's Subtree  

      12.7 Parsing Microsoft Excel's XML  

      12.8 Validating XML Documents  

      12.9 Filtering Elements and Attributes Belonging to a Given Namespace  

      12.10 Merging Continuous Text Events with a SAX Filter  

      12.11 Using MSHTML to Parse XML or HTML  

13. Network Programming

      13.1 Passing Messages with Socket Datagrams  

      13.2 Grabbing a Document from the Web  

      13.3 Filtering a List of FTP Sites  

      13.4 Getting Time from a Server via the SNTP Protocol  

      13.5 Sending HTML Mail  

      13.6 Bundling Files in a MIME Message  

      13.7 Unpacking a Multipart MIME Message  

      13.8 Removing Attachments from an Email Message  

      13.9 Fixing Messages Parsed by Python 2.4 email.FeedParser  

      13.10 Inspecting a POP3 Mailbox Interactively  

      13.11 Detecting Inactive Computers  

      13.12 Monitoring a Network with HTTP  

      13.13 Forwarding and Redirecting Network Ports  

      13.14 Tunneling SSL Through a Proxy  

      13.15 Implementing the Dynamic IP Protocol  

      13.16 Connecting to IRC and Logging Messages to Disk  

      13.17 Accessing LDAP Servers  

14. Web Programming

      14.1 Testing Whether CGI Is Working  

      14.2 Handling URLs Within a CGI Script  

      14.3 Uploading Files with CGI  

      14.4 Checking for a Web Page's Existence  

      14.5 Checking Content Type via HTTP  

      14.6 Resuming the HTTP Download of a File  

      14.7 Handling Cookies While Fetching Web Pages  

      14.8 Authenticating with a Proxy for HTTPS Navigation  

      14.9 Running a Servlet with Jython  

      14.10 Finding an Internet Explorer Cookie  

      14.11 Generating OPML Files  

      14.12 Aggregating RSS Feeds  

      14.13 Turning Data into Web Pages Through Templates  

      14.14 Rendering Arbitrary Objects with Nevow  

15. Distributed Programming

      15.1 Making an XML-RPC Method Call  

      15.2 Serving XML-RPC Requests  

      15.3 Using XML-RPC with Medusa  

      15.4 Enabling an XML-RPC Server to Be Terminated Remotely  

      15.5 Implementing SimpleXMLRPCServer Niceties  

      15.6 Giving an XML-RPC Server a wxPython GUI  

      15.7 Using Twisted Perspective Broker  

      15.8 Implementing a CORBA Server and Client  

      15.9 Performing Remote Logins Using telnetlib  

      15.10 Performing Remote Logins with SSH  

      15.11 Authenticating an SSL Client over HTTPS  

16. Programs About Programs

      16.1 Verifying Whether a String Represents a Valid Number  

      16.2 Importing a Dynamically Generated Module  

      16.3 Importing from a Module Whose Name Is Determined at Runtime  

      16.4 Associating Parameters with a Function (Currying)  

      16.5 Composing Functions  

      16.6 Colorizing Python Source Using the Built-in Tokenizer  

      16.7 Merging and Splitting Tokens  

      16.8 Checking Whether a String Has Balanced Parentheses  

      16.9 Simulating Enumerations in Python  

      16.10 Referring to a List Comprehension While Building It  

      16.11 Automating the py2exe Compilationof Scripts into Windows Executables  

      16.12 Binding Main Script and Modules into One Executable on Unix  

17. Extending and Embedding

      17.1 Implementing a Simple Extension Type  

      17.2 Implementing a Simple Extension Type with Pyrex  

      17.3 Exposing a C++ Library to Python  

      17.4 Calling Functions from a Windows DLL  

      17.5 Using SWIG-Generated Modules in a Multithreaded Environment  

      17.6 Translating a Python Sequence into a C Arraywith the PySequence_Fast Protocol
      17.7 Accessing a Python Sequence Item-by-Item with the Iterator Protocol  

      17.8 Returning None from a Python-Callable C Function  

      17.9 Debugging Dynamically Loaded C Extensions with gdb  

      17.10 Debugging Memory Problems  

18. Algorithms

      18.1 Removing Duplicates from a Sequence  

      18.2 Removing Duplicates from a SequenceWhile Maintaining Sequence Order  

      18.3 Generating Random Samples with Replacement  

      18.4 Generating Random Samples Without Replacement  

      18.5 Memoizing (Caching) the Return Values of Functions  

      18.6 Implementing a FIFO Container  

      18.7 Caching Objects with a FIFO Pruning Strategy  

      18.8 Implementing a Bag (Multiset) Collection Type  

      18.9 Simulating the Ternary Operator in Python  

      18.10 Computing Prime Numbers  

      18.11 Formatting Integers as Binary Strings  

      18.12 Formatting Integers as Strings in Arbitrary Bases  

      18.13 Converting Numbers to Rationals via Farey Fractions  

      18.14 Doing Arithmetic with Error Propagation  

      18.15 Summing Numbers with Maximal Accuracy  

      18.16 Simulating Floating Point  

      18.17 Computing the Convex Hulls and Diameters of 2D Point Sets  

19. Iterators and Generators

      19.1 Writing a range-like Function with Float Increments  

      19.2 Building a List from Any Iterable  

      19.3 Generating the Fibonacci Sequence  

      19.4 Unpacking a Few Items in a Multiple Assignment  

      19.5 Automatically Unpacking the Needed Number of Items  

      19.6 Dividing an Iterable into n Slices of Stride n  

      19.7 Looping on a Sequence by Overlapping Windows  

      19.8 Looping Through Multiple Iterables in Parallel  

      19.9 Looping Through the Cross-Product of Multiple Iterables  

      19.10 Reading a Text File by Paragraphs  

      19.11 Reading Lines with Continuation Characters  

      19.12 Iterating on a Stream of Data Blocks as a Stream of Lines  

      19.13 Fetching Large Record Sets from a Database with a Generator  

      19.14 Merging Sorted Sequences  

      19.15 Generating Permutations, Combinations, and Selections  

      19.16 Generating the Partitions of an Integer  

      19.17 Duplicating an Iterator  

      19.18 Looking Ahead into an Iterator  

      19.19 Simplifying Queue-Consumer Threads  

      19.20 Running an Iterator in Another Thread  

      19.21 Computing a Summary Report with itertools.groupby  

20. Descriptors, Decorators, and Metaclasses

      20.1 Getting Fresh Default Values at Each Function Call  

      20.2 Coding Properties as Nested Functions  

      20.3 Aliasing Attribute Values  

      20.4 Caching Attribute Values  

      20.5 Using One Method as Accessor for Multiple Attributes  

      20.6 Adding Functionality to a Class by Wrapping a Method  

      20.7 Adding Functionality to a Class by Enriching All Methods  

      20.8 Adding a Method to a Class Instance at Runtime  

      20.9 Checking Whether Interfaces Are Implemented  

      20.10 Using _ _new_ _ and _ _init_ _ Appropriately in Custom Metaclasses  

      20.11 Allowing Chaining of Mutating List Methods  

      20.12 Using Cooperative Supercalls with Terser Syntax  

      20.13 Initializing Instance Attributes Without Using _ _init_ _  

      20.14 Automatic Initialization of Instance Attributes  

      20.15 Upgrading Class Instances Automatically on reload  

      20.16 Binding Constants at Compile Time  

      20.17 Solving Metaclass Conflicts  

Index