Algorithms For Dummies

 

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Reduce development time

 

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Reduce programmer error

 

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Increase application reliability

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78

 

   

  PART 1 

 Getting Started

 

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Allow entire groups to benefit from the work of one programmer

 

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Make code easier to understand

 

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Improve application efficiency

In fact, functions do a whole list of things for applications in the form of reus-

ability. As you work through the examples in this book, you see how reusability 

makes your life significantly easier. If not for reusability, you’d still be program-

ming by plugging 0s and 1s into the computer by hand.

Creating a function doesn’t require much work. To see how functions work, open 

a copy of IPython and type in the following code (pressing Enter at the end of  

each line):

def SayHello():

    print('Hello There!')

To end the function, you press Enter a second time after the last line. A function 

begins with the keyword 

def

 (for define). You provide a function name, parenthe-

ses that can contain function arguments (data used in the function), and a colon. 

The editor automatically indents the next line for you. Python relies on whitespace 

to  define  code blocks (statements that are associated with each other in a 

function).

You can now use the function. Simply type SayHello() and press Enter. The paren-

theses after the function name are important because they tell Python to execute 

the function rather than tell you that you are accessing a function as an object (to 

determine what it is). You see 

Hello There!

 as the output.