From a most interesting Saturday which was spent doing a one on one session on thread, wxPython, etc - some Python snippets that provide unusual demos and hard-to-find answers:
The Backtic operator evaluates an expression and returns the result as a string
val1 = 16
val2 = 18
result = "The result is "+`val1 + val2`
print result
If you want to have various bits of code running at the same time you can use
piping, or you can use
threads, or you can use
a client / server system via TCP/IP.
We have
an example of Python threading and
a python tcp/ip client and
a simple python server all available on this web site. Piping is especially useful if you're containing / running an outside process on your machine, threads are useful where you're processing the same type of data in parallel many times over, and a client / server architecture is ideally suited to a logger and display application, with a server logging and one or more client, perhaps on remote computers, displaying.
The wxPython module provides an excellent GUI - in other words an excellent way to provide a user interface on the front of your Python code. However, there's a lack of good worked learning examples. I've just added more source code examples - linkable from our
wxPython training course module. These examples were originally based on other published code, but have been extensively rearranged for clarity and commented.
The super call only works on new style classes!.
If you try to use "super" on old syle classes, you'll be told "
TypeError: super() argument 1 must be type, not instance
".
Old style classes ...
# old style classes
class thing:
def __init__(self):
pass
class specialthing(thing):
def __init__(self):
thing.__init__(self)
this = specialthing()
New style classes ...
# new style classes
class thing(object):
def __init__(self):
pass
class specialthing(thing):
def __init__(self):
super(specialthing,self).__init__()
this = specialthing()
What are new style classes? .... they're classes that are derived, directly or indirectly, from built in classes and they've been around since Python 2.2. As well as super, other new features include the ability to define static and class methods, rather than just a method in the same namespace. more details (external link)
We offer Python training courses. If you've just one or two people to be trained, our
public courses which run every 2 or 3 months are going to be best value. For slightly larger groups, we'll run a
private course at our centre. With 6 or more delegates all wanting to learn the same material at the same time,
we'll come to you - you just provide a room and the students, we do the rest!
(written 2006-10-23, updated 2006-11-01)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
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Y207 - wxPython [2013] wxPython - Introduction and sample - (2009-01-29)
[2744] PyQt (Python and Qt) and wxPython - GUI comparison - (2010-04-28)
[2887] Snow Leopard and Python (that is OS X 10.6 and wxPython) - (2010-07-26)
[3081] wxPython - simple example to add GUI to a server log file analysis - (2010-12-08)
[3086] Sizers (geometry control) in a wxPython GUI - a first example - (2010-12-15)
[3092] wxPython geometry - BoxSizer example - (2010-12-17)
[3139] Steering our Python courses towards wxPython, SQLite and Django - (2011-01-19)
[4589] Principles or a GUI and their practical application using wxPthon - (2015-11-30)
Y202 - Python on the Web [237] Crossfertilisation, PHP to Python - (2005-03-06)
[426] Robust checking of data entered by users - (2005-08-27)
[433] FTP - how to make the right transfers - (2005-09-01)
[1745] Moodle, Drupal, Django (and Rails) - (2008-08-08)
[2238] Handling nasty characters - Perl, PHP, Python, Tcl, Lua - (2009-06-14)
[2365] Counting Words in Python via the web - (2009-08-18)
[4089] Quick and easy - showing Python data hander output via a browser - (2013-05-15)
[4404] Which (virtual) host was visited? Tuning Apache log files, and Python analysis - (2015-01-23)
[4536] Json load from URL, recursive display, Python 3.4 - (2015-10-14)
Y112 - Python - Objects - Intermediate [296] Using a Python dictionary as a holder of object attributes - (2005-04-30)
[383] Overloading of operators on standard objects in Python - (2005-07-19)
[477] Class, static and unbound variables - (2005-10-25)
[656] Think about your design even if you don't use full UML - (2006-03-24)
[831] Comparison of Object Oriented Philosophy - Python, Java, C++, Perl - (2006-08-13)
[964] Practical polymorphism in action - (2006-12-04)
[1146] __new__ v __init__ - python constructor alternatives? - (2007-04-14)
[1217] What are factory and singleton classes? - (2007-06-04)
[1517] Python - formatting objects - (2008-01-24)
[1644] Using a utility method to construct objects of different types - Python - (2008-05-17)
[1661] Equality, sameness and identity - Python - (2008-05-31)
[1819] Calling base class constructors - (2008-10-03)
[2368] Python - fresh examples of all the fundamentals - (2009-08-20)
[2409] TypeError: super() argument 1 must be type, not classobj (Python) - (2009-09-18)
[2485] How do I set up a constant in Python? - (2009-10-31)
[2693] Methods that run on classes (static methods) in Python - (2010-03-25)
[2717] The Multiple Inheritance Conundrum, interfaces and mixins - (2010-04-11)
[2720] Multiple inheritance in Python - complete working example - (2010-04-14)
[2722] Mixins example in Python - (2010-04-14)
[2764] Python decorators - your own, staticmethod and classmethod - (2010-05-14)
[2785] The Light bulb moment when people see how Object Orientation works in real use - (2010-05-28)
[2889] Should Python classes each be in their own file? - (2010-07-27)
[2905] Defining static methods in Python - (2010-08-05)
[2994] Python - some common questions answered in code examples - (2010-10-10)
[3002] A list of special method and attribute names in Python - (2010-10-17)
[3442] A demonstration of how many Python facilities work together - (2011-09-16)
[3472] Static variables in functions - and better ways using objects - (2011-10-10)
[3524] Metaclasses (Python) and Metatables (Lua) - (2011-11-17)
[3796] Backquote, backtic, str and repr in Python - conversion object to string - (2012-07-05)
[3887] Inheritance, Composition and Associated objects - when to use which - Python example - (2012-10-10)
[4028] Really Simple Class and Inheritance example in Python - (2013-03-04)
[4094] Python Properties - how and why - (2013-05-18)
[4344] Python base and inherited classes, test harness and unit testing - new examples - (2014-12-07)
[4356] Object factories in C++, Python, PHP and Perl - (2014-12-19)
[4366] Changing what operators do on objects - a comparison across different programming languages - (2014-12-26)
[4410] A good example of recursion - a real use in Python - (2015-02-01)
[4449] Spike solution, refactoring into encapsulated object methods - good design practise - (2015-03-05)
[4450] Deciding whether to use parameters, conditional statements or subclasses - (2015-03-05)
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[4718] Defining an object that is a modified standard type in Python - (2016-11-02)
[4719] Nesting decorators - (2016-11-02)
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[463] Splitting the difference - (2005-10-13)
[496] Python printf - (2005-11-15)
[560] The fencepost problem - (2006-01-10)
[773] Breaking bread - (2006-06-22)
[943] Matching within multiline strings, and ignoring case in regular expressions - (2006-11-25)
[954] Splitting Pythons in Bradford - (2006-11-29)
[970] String duplication - x in Perl, * in Python and Ruby - (2006-12-07)
[1110] Python - two different splits - (2007-03-15)
[1195] Regular Express Primer - (2007-05-20)
[1608] Underlining in Perl and Python - the x and * operator in use - (2008-04-12)
[1876] Python Regular Expressions - (2008-11-08)
[2284] Strings as collections in Python - (2009-07-12)
[2406] Pound Sign in Python Program - (2009-09-15)
[2692] Flexible search and replace in Python - (2010-03-25)
[2721] Regular Expressions in Python - (2010-04-14)
[2765] Running operating system commands from your Python program - (2010-05-14)
[2780] Formatted Printing in Python - (2010-05-25)
[2814] Python - splitting and joining strings - (2010-06-16)
[3090] Matching to a string - what if it matches in many possible ways? - (2010-12-17)
[3218] Matching a license plate or product code - Regular Expressions - (2011-03-28)
[3349] Formatting output in Python through str.format - (2011-07-07)
[3468] Python string formatting - the move from % to str.format - (2011-10-08)
[3469] Teaching dilemma - old tricks and techniques, or recent enhancements? - (2011-10-08)
[3886] Formatting output - why we need to, and first Python example - (2012-10-09)
[4027] Collections in Python - list tuple dict and string. - (2013-03-04)
[4152] Why are bus fares so high? - (2013-08-18)
[4213] Formatting options in Python - (2013-11-16)
[4307] Identifying and clearing denial of service attacks on your Apache server - (2014-09-27)
[4360] Python - comparison of old and new string formatters - (2014-12-22)
[4593] Command line parameter handling in Python via the argparse module - (2015-12-08)
[4595] Python formatting update - including named completions - (2015-12-10)
[4659] Prining a pound sign from Python AND running from the command line at the same time - (2016-03-03)
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