Python learns day-5 variables and recursive functions

First, local variables and global variables

Name= ' LHF ' global variables


Def change_name ():
Global name globally variable without global is local variable
Name= ' Handsome a ratio '
Print (' Change_name ', name)


Change_name ()
Print (name)

Name= ' LHF '

Def change_name ():
Name1= ' Handsome a ratio '
Name2= ' Handsome a ratio '
Name3= ' Handsome a ratio '
Print (' Change_name ', name)

Globals keywords

NAME = "Slash"

Def Yangjian ():
Global NAME
NAME = "Little Northeast"
Print (' I'm going to do ', NAME)

Def Qupengfei ():
Print (' I'm going to do ', NAME)

Yangjian ()
Qupengfei ()
--------------------------------------------------


NAME = "Product Manager"

Def Yangjian ():
# NAME = "History text"
Global name # has declared that name is the global variable
Print (' I'm going to do ', NAME)
NAME = "Little Northeast" # Modify global variables
Print (' I'm going to do ', NAME)

Def Qupengfei ():
NAME = "Base"
Print (' I'm going to do ', NAME)

If the contents of the function have no global keyword,
-have declared local variables
NAME = ["Product Manager", "Riopo Wet"]
Def Qupengfei ():
NAME = "Self"
Print (' I'm going to do ', NAME)
Qupengfei ()
-No declaration of local variables
NAME = ["Product Manager", "Riopo Wet"]
Def Qupengfei ():
Name.append (' Xxoo ')
Print (' I'm going to do ', NAME)
Qupengfei ()

If the contents of the function have the global keyword
-have declared local variables
NAME = ["Product Manager", "Riopo Wet"]
Def Qupengfei ():
Global NAME
NAME = "Self"
Print (' I'm going to do ', NAME)
Qupengfei ()
Error example
NAME = ["Product Manager", "Riopo Wet"]
Def Qupengfei ():
NAME = "Self"
Global NAME
Print (' I'm going to do ', NAME)
Qupengfei ()
-No declaration of local variables
NAME = ["Product Manager", "Riopo Wet"]
Def Qupengfei ():
Global NAME
NAME = ["Mao"]
Name.append (' Xxoo ')
Print (' I'm going to do ', NAME)
Qupengfei ()

####### global variable name capitalization
####### local variable variable name lowercase


Local variables are read first, global variables can be read, global variables cannot be re-assigned name= "FFF", but for mutable types, internal elements can be manipulated
If there is a global keyword in the function, the variable is essentially the global variable and can read the assignable name= "FFF"





NAME = ' Sea Breeze '

Def Huangwei ():
Name = "Huang Wei"
Print (name)
Def Liuyang ():
Name = "Liu Yang"
Print (name)
Def nulige ():
name = ' Prev Flower '
Print (name)
Print (name)
Nulige ()
Liuyang ()
Print (name)

Huangwei ()

Name = "Just Niang"

Def Weihou ():
    Name = "Chen Zhuo"
    Def Weiweihou ():
        nonlocal name   # nonlocal, specify the upper-level variable, and if not, continue up until you find it
        Name = "Cool"

    Weiweihou ()
    Print (name)

Print (name)
Weihou ()
Print (name)








Second, forward reference

Example one: Error
def foo ():
    Print (' from foo ')
    Bar ()

Foo ()
Example 2
def bar ():
    Print (' from Bar ')
def foo ():
    Print (' from foo ')
    Bar ()

Foo ()


Example 3
def foo ():
    Print (' from foo ')
    Bar ()

def bar ():
    Print (' from Bar ')
Foo ()
Example 4: Error
def foo ():
    Print (' from foo ')
    Bar ()

Foo ()

def bar ():
    Print (' from Bar ')

1
Def calc (n):
    Print (n)
    if int (N/2) = = 0:
        return n
    Res=calc (int (N/2))
    return res



2

Import time

Person_list = [' Alex ', ' Wupeiqi ', ' Linhaifeng ', ' ZSC ']


def ask_way (person_list):
    Print ('-' * 60)
    If Len (person_list) = = 0:
        Return ' No one Knows '
    person = person_list.pop (0)
    if person = = ' Linhaifeng ':
        Return '%s ' said: I know, the old boy is in Shahe Tak Commercial building, under the subway is '% person

    Print (' Hi-man [%s], dare to ask where the road is '% person ')
    Print ('%s ' replied: "I don't know, but read your eyes to the pig, you wait, I help you ask%s ... '% (person, person_list))
    Time.sleep (1)
    res = Ask_way (person_list)

    Print ('%s ' results were:%res '% (person, res))
    return res


res = Ask_way (person_list)
Print (RES)

Python learns day-5 variables and recursive functions