loop

I. for cycle

1. The real use is for iterative objects:
1) List: a = [1,2,3,4,5,[1,2,3],'aduh']
2) tuple: a = [1,2,3,[1,2,3],'aduh']
3) Dictionary: a = {key':'value','akdfg','list': [1,2,3],'tuple': [1,2,3]}
4) Sets: a = 1,2,4,2}
2. Counting function:

#range starts at 0 and defaults to 1
for i in range(10):
    print(i)

range generates an invariant sequence of values:
1) range(101) can produce an integer sequence of 0 to 100.
2) range (1,100) can produce an integer sequence of 1 to 99.
3) range(1, 100, 2) can produce an odd sequence of 1 to 99, of which 2 is the step size, i.e. the increment of the numerical sequence.

for i in range(10，0，-2):
    print(i)
#Results: 10, 8, 6, 4, 2

a = [1,2,3]
for i in a:
    print(i)
#Result
#1
#2
#3

a = [2,1,3]
a.sort(reverse = True)
print(a)
#Results: [1, 2, 3]

3, iteration

for i in range(5):
    for j in range(5):
        for k in range(5):
            print(k)

Exercise: 9x9 multiplication table

for i in range(1,10):
    for j in range(1,10):
        if i >= j:
            k = i * j
            print("%d x %d = %d"%(j,i,k),end = "\t") 
    print()
#Method 2
for i in range(1,10):
    for j in range(1,i + 1):
            print("%d x %d = %d"%(j,i,k),end = "\t") 
    print()

2. while loops (generally used for dead loops)

#Traversal with while
str_ = 'Joker is a bod man!'
i = 0
while i < len(str_):
    print(str_[i])
    i += 1

3. Circulation exercises

#Luck draw:
#1. Running kart: (1. Peak, 2. Toilet car, 3. Panda car, 4. Thank you for your patronage)
#2.10 yuan a time, until no money, no money can be flushed
#3. After recharging to a certain amount, pay attention to game health and rational consumption
#4. Peak's winning probability is 0.0001%.

import random
money = 40
j = 0
for j in range(1000):
    print("Your balance is:%d"%money)
    for i in range(money):
        a = int(input("Whether to draw (1).Yes, 2.No):"))
        if a == 1:
            if money >= 10:
                print("A raffle kart:")
                wanjia = random.randint(0,10000)
                print("The number you drew is ____________.%d"%wanjia)
                if wanjia == 1:
                    print("Congratulations on your winning the pinnacle")
                
                elif 1000 <= wanjia <= 2000:
                    print("Congratulations on your winning the toilet car") 
                    
                elif 4000 <= wanjia <= 6000:
                    print("Congratulations on your winning the Panda Car") 
                    
                else:
                    print("I'm sorry you didn't win the prize.")
                    money -= 10        
            else:
                print("The balance is insufficient. Please draw after recharging.")
                money1 = int(input("Please recharge:"))
                money += money1
                print("Your balance is%d"%money1)
                j += 1
        else:
            break
    if j > 3:
        print("**********Pay attention to game health and rational consumption***********")

function

First, role

Simplify the code. When you need to repeat some code and make only minor changes, you can use functions.

Two, structure

def func_name([params]):
    //Executive body
    return xxx

def Apple(end):
    fm = 1
    for i in range(1,end + 1):
        fm *= i
    return fm

num1 = Apple(7)
num2 = Apple(3)
num3 = Apple(4)
print(num1 / (num2 * num3)) 
#Results: 35.0

Three, practice

#Log in to the mailbox. In the form of a function, the account is a function and the password is a function.
def zhang():
    hao = input("Login account:")
    return hao
def mi():
    ma = input("Login password:")
    return ma

def Start():
    z = zhang()
    m = mi()
    if m == '54685' and z == '56552':
        print("Login successfully")
    else:          
        print("Error in account or password")  
Start()

#Good friends
#1. Add Friends
#2. Find out if you have friends
#3. If so, return and wait for the other party's consent - > leave a message

def add(name):
    names = ['dfg','dsfd','df']
    if name in names:
        Print_or_mess()
    else:
        print("The user does not exist")
def Print_or_mess():
    print("Added, waiting for the other party's consent")
    res = input('Do you leave messages?[y/n]')
    if res == 'y':
        input("Please enter a message:")

def Start():
   name = input("Please enter a user name:")
   add(name)
Start()

#Secretly add back deleted friends.

money = 0

def you(name):
    names = ['dfg','dsfd','df']
    if name in names:
        print("This user is already your friend.")
    else:
        chong()

def chong():
    global money  #global variable
    if money >= 100:
        print("You have succeeded in sneaking in friends")
        money -= 100
    else:
        print("Your fee is insufficient. Please recharge it. VIP")
        res = input('Whether to recharge[y/n]')
        if res == 'y':
            print("It's jumping....")
            res1 = float(input('Recharge amount:'))
            money += res1
            chong()
        else:
            print("Add failure")

def Star():
    name = input("Please enter the friends you want to add:")
    you (name)
Star()