python--function

function

Definition of the function:

def function name ():

function body

Return returns a value of 1, which returns a value of 2.

Call to function:

Name of function ()

? Implement print return value : Print function name ()

? Summary :

- function is not executed when the function is defined ;

- function is executed only when the function is called ;

function with parameters

Required Parameters

# Formal Parameters

# Arguments , x=1, y=2;

Add(1 2)

3

Default parameters

def mypow (x,y=2):

Print X**y

Variable parameters

# Formal Parameters

# args can be changed to other variable names ;

def add (*args):

# args is essentially a tuple ;

# Print Args

sum = 0

For i in args:

sum + = i

Print sum

Keyword parameters

# Kwargs can be changed to another variable name ;

def inuser (name, age, **kwargs):

# Kwargs is essentially a dictionary ;

Print name, name, Kwargs

Inuser ("user1" city= "Xi ' an" birth= "20180101")

default Parameters , > variable Parameters , > keyword Parameters

return value

If there is no return in the function , the default return is none;

Return multiple values

  

Scope of the function

The global keyword must first be declared and then assigned ;

# Global Variables

Advanced Features

Slice

Iteration

? Whether you can for the object that iterates through ;

Isinstance Judge whether the iteration can be iterative ;

List-Generated

? formulas for generating lists

? Demand : Generate a list , return 1-100 The square of the even number ;([4, .....]

# Method 1:

# Method 2:

[I**2 for I in range (2 20 2)]

[4, 16, 36, 64, 100, 144, 196, 256, 324]

Variant list of generated formula

# for loop nested if statement

# for loop nested for Loop, two string full array

python--function