Definition of Python function

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Catalog

• • • One 、 background
    • Two 、 Definition of function
    • 3、 ... and 、 Reference resources
    • Four 、 summary

One 、 background

In the actual development process , You will often encounter many identical or very similar operations , At this time , Code that implements similar operations can be encapsulated as functions , Then call the function where you need it . This can not only realize code reuse , It can also make the code more organized , Increase code reliability . Now let's introduce python Definition of .

Two 、 Definition of function

• A function is a segment of 、 Reusable code snippets , It can improve the modularity of program and the reuse rate of code .
• Python Provides a lot of built-in functions （ Such as print()、input()、int() Functions, etc ）
• Standard library functions （ Such as math In the library sqrt() function ）
• Users can also write their own functions , It's called a custom function .

stay Python in , The general form of defining a function is ：

• Use def Keyword to define the function
• The function name can be any valid Python identifier
• In parentheses after the function name is a list of formal parameters （ It's called formal parameter for short ）, The formal parameter list is the value passed to the function when it is called , There can be zero 、 One or more , When multiple parameters are passed, they are separated by commas .
• The function body is the code executed each time a function is called , Consisting of one or more lines of statements .

def Function name ([ List of formal parameters ]):
The body of the function

Be careful ：
（1） Even if the function doesn't need to take any arguments , You also have to keep a pair of empty parentheses .
（2） The colon after the bracket cannot be omitted .
（3） The function body is relative to def Keywords must keep a certain space indentation .
for example ： Definition is named “print_text()” Function of , The function is output “Hello world!”

def print_text():
print("Hello world!")

3、 ... and 、 Reference resources

1、 Liao Xuefeng's official website
2、python Official website
3、Python Programming case tutorial

Four 、 summary

The above is about Python Definition of , You can refer to it , If you think it's good , Welcome to thumb up 、 Collection 、 Looking at , Welcome to wechat search java Basic notes , Relevant knowledge will be continuously updated later , Make progress together .