This section of our beginning python training class always stumps students.  Firstly, because they need to know the difference between a function and a method.  Secondly, they need to understand object oriented programming concepts.  Thirdly, they need to realize that python has three types of methods.  Then they need to know how to use each method, which means they need to know the purpose of each method type.  Then they have to understand mutable versus non-mutable types.  The list goes on.  As part of our python tutorial, I hope to shed some light on this confusing topic.

To begin, the difference between a function and a method in python is that a method is defined within a class.  Here is an illustration:

#function

	def greeting():
	                print "Hello, I hope you're having a great day!"

	class HSGPrinter(object):
	                #method
	                def greeting(self): 
	                                print "Hello, I hope you're having a great day!"

As should be obvious, the second definition of greeting is encapsulated within the HSGPrinter class and is , therefore, refered to as a method.

The astute reader will notice that the greeting method contains one parameter named self.  For those who know C++ , Java or C#, self is equivalent to this i.e. it is a reference to the invoking object:

Recently, I asked my friend, Ray, to list those he believes are the top 10 most forward thinkers in the IT industry.  Below is the list he generated. 

Like most smart people, Ray gets his information from institutions such as the New York Times, the Wall Street Journal, the Huffington Post, Ted Talks ...  Ray is not an IT expert; he is, however, a marketer: the type that has an opinion on everything and is all too willing to share it.  Unfortunately, many of his opinions are based upon the writings/editorials of those attempting to appeal to the reading level of an 8th grader.  I suppose it could be worse.  He could be referencing Yahoo News, where important stories get priority placement such as when the voluptuous Kate Upton holds a computer close to her breasts.

Before you read further, note that missing from this list and not credited are innovators: Bill Joy, Dennis Ritchie, Linus Torvalds, Alan Turing, Edward Howard Armstrong, Peter Andreas Grunberg and Albert Fent, Gottfried Wilhelm Leibniz/Hermann Grassmann ... You know the type:  the type of individual who burns the midnight oil and rarely, if ever, guffaws over their discoveries or achievements.

C# PROGRAMMING –MAIN DESIGN GOALS

C# is a popular programming language these days, and it was designed from inception to provide a simple, clean, general purpose programming language for those intending to work within the confines of Microsoft’s .NET framework.  Since then, it has been approved as one of the standard languages by both ECMA and ISO, making C# programming an essential tool in every programmers’ kit.

Different languages have different uses and specialties, and C# was designed for programmers to be able to use it to create different components for use in software that would be deployed and distributed en masse, to live use environments.  This means that designers had to really put an emphasis on making the actual source code extremely compatible and portable.  Those already familiar with C or C++ should definitely notice this emphasis.

Another particular point of emphasis during design was focus on internationalization of the language; it was intended from inception to be available all over the world, and to see all sorts of different implementations based on variance in regional programming technique.  The resultant use should help the language develop sophistication as it is refined throughout different versions.

It is said that spoken languages shape thoughts by their inclusion and exclusion of concepts, and by structuring them in different ways. Similarly, programming languages shape solutions by making some tasks easier and others less aesthetic. Using F# instead of C# reshapes software projects in ways that prefer certain development styles and outcomes, changing what is possible and how it is achieved.

F# is a functional language from Microsoft's research division. While once relegated to the land of impractical academia, the principles espoused by functional programming are beginning to garner mainstream appeal.

As its name implies, functions are first-class citizens in functional programming. Blocks of code can be stored in variables, passed to other functions, and infinitely composed into higher-order functions, encouraging cleaner abstractions and easier testing. While it has long been possible to store and pass code, F#'s clean syntax for higher-order functions encourages them as a solution to any problem seeking an abstraction.

F# also encourages immutability. Instead of maintaining state in variables, functional programming with F# models programs as a series of functions converting inputs to outputs. While this introduces complications for those used to imperative styles, the benefits of immutability mesh well with many current developments best practices.

For instance, if functions are pure, handling only immutable data and exhibiting no side effects, then testing is vastly simplified. It is very easy to test that a specific block of code always returns the same value given the same inputs, and by modeling code as a series of immutable functions, it becomes possible to gain a deep and highly precise set of guarantees that software will behave exactly as written.

Further, if execution flow is exclusively a matter of routing function inputs to outputs, then concurrency is vastly simplified. By shifting away from mutable state to immutable functions, the need for locks and semaphores is vastly reduced if not entirely eliminated, and multi-processor development is almost effortless in many cases.

Type inference is another powerful feature of many functional languages. It is often unnecessary to specify argument and return types, since any modern compiler can infer them automatically. F# brings this feature to most areas of the language, making F# feel less like a statically-typed language and more like Ruby or Python. F# also eliminates noise like braces, explicit returns, and other bits of ceremony that make languages feel cumbersome.

Functional programming with F# makes it possible to write concise, easily testable code that is simpler to parallelize and reason about. However, strict functional styles often require imperative developers to learn new ways of thinking that are not as intuitive. Fortunately, F# makes it possible to incrementally change habits over time. Thanks to its hybrid object-oriented and functional nature, and its clean interoperability with the .net platform, F# developers can gradually shift to a more functional mindset while still using the algorithms and libraries with which they are most familiar.

Related F# Resources:

F# Programming Essentials Training