Python3 functions -python introduction to mastery

Preface

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function

A function is a reusable 、 A block of code that implements a specific function .
The feature of the function is that it can improve the application Modularity , And code reusability .

grammar

Python Define function use def keyword , The general format is as follows ：

def Function name （ parameter list ）:
The body of the function

We need to pay attention to the following ：

• Function code block to def Key words start with , Followed by function identifier name and parentheses ().
• Any arguments and arguments passed in must be placed between parentheses , Parentheses can be used to define parameters .
• The first line of the function optionally uses the document string , Used to store function descriptions .
• Function contents start with a colon , And indent .
• return [ expression ] End function , Optionally return a value to the caller . Without expression return It's equivalent to returning to None .

for instance

Let's write a function , For output Hello Python! .

def hello():
print("Hello Python!")

Add a comment to the function .

def hello():
""" Output Hello """
print("Hello Python!")

Add a parameter , And set default values for parameters .

def hello(name='Python'):
""" Output Hello """
print("Hello " + name + "!")

Set return value , If we do not set up , The default return value is None .

def hello(name='Python'):
""" Output Hello """
print("Hello " + name + "!")
return 'ok'

Call function .

def hello(name='Python'):
""" Output Hello """
print("Hello " + name + "!")
return 'ok'
h = hello()
print(h)

Exercises

Find out the errors and irregularities in the following code .

def getMax(a=0, b = 0, c)
''' return a,b,c The largest of the three numbers '''
if a >= b and a > c:
return a;
elseif b > a && b > c:
return b
else:
return c
return None

Official account ： Pangao will accompany you to learn programming , reply 018, Get the answer to the exercise .