Python Certification Training in Toronto Canada

Python Functions:

• • Why Need Python Functions?
  • What are Python Functions?
  • Types of Python Functions

• • Functions manage the inputs and outputs in computer programs. Programming languages are designed to work on data and functions are an effective way to manage and transform this data.
  • The modifications are generally done to drive outcomes like performing tasks and finding results. And, the set of operations or instructions required to do so comes from logically functional blocks of code that can be reused independently from the main program.
  • In fact, the main code is also a function, just a very important one at that. Every other function is logically aligned and maintained to functionally execute from your main code. But, if the function has not been defined previously, you will just have to define one yourself before using it. This is because the definition lists the steps of its operation.

• • The functions in Python are a classic example of such re-usability. So, to serve a wide range of applications from GUI and mathematical computing to web development and testing, Pythons interpreter already comes equipped with numerous functions that are always available for use. And, you could also bring in other libraries or modules to your program that contain pre-defined functions readily available for use.
  • All you will really have to do is download required packages that according to their documentation and freely avail all its useful functionalities by just importing them over to your code.
  • So, once defined, a function can be used any number of times at any point in any of your codes. Now, this is because Python falls in-line with the DRY principle of software engineering, which aims to replace any repetition of software patterns or codes with abstractions to avoid redundancy and ensure that they can be used freely without revealing any inner details on their implementations.
  • DRY expands to Do not Repeat Yourself and this concept of having re-usable blocks of codes is very crucial for achieving abstraction in Python. Thus, in order to use a function all that you will really need is its name, its purpose, its arguments if it takes any and its results type if it returns any.
  • Its almost like using an automobile or a telephone, where you do not necessarily need to understand the working of its components to use them. Rather, they have been already built to serve common purposes that you can just use directly to achieve your goals and devote your precious time to implementing all the innovative aspects of your application program. And, nobody really wants to know how a function in your program works on the inside, as long as it does the job.
  • So, with Python, unless you must write a new function or change how an existing one works, you even need to understand anything about what goes on inside till it works the way you need it to. It just like with a vehicle or a phone again, where you will need to know how it works in order to build or fix one. And, similarly, once you have written a working function, you can use it repeatedly without having to look at the contents inside it ever again.
  • A function can be called as a section of a program that is written once and can be executed whenever required in the program, thus making code re-usability.
  • The function is a subprogram that works on data and produces some output.
  • To define a Python function, you did have to use the keyword before the name of your function and add parentheses to its end, followed by a colon(:).
  • Python uses indentation to indicate blocks instead of brackets to make codes more readable.
  • A function in Python may contain any number of parameters or none. So, for times when you need your function to operate on variables from other blocks of code or from your main program, it could take any number of parameters and produce results.
  • A Python function could also optionally return a value. This value could be a result produced from your functions execution or even be an expression or value that you specify after the keyword return. And, after a return statement is executed, the program flow goes back to the state next to your function call and gets executed from there.

• Python Built-in Functions
• Python Recursion Functions
• Python Lambda Functions
• Python User-defined Functions