Python Learning Note 2

#!/usr/bin/python3#-*- coding:utf-8 -*-id_db = {     3713131131:{       ' name '  :  ' Chenhao ',        ' age ': 22,       ' addr '  :  ' Shandong '     },    33333131131: {          ' name ':  "Chen",         ' age ': 24,          ' addr ':  "Dongbei"     }, #修改和添加字典print (id_db[ 3713131131]) id_db[3713131131][' name ']= "Wang" id_db[3713131131][' QQ ']=2322345del id_db[3713131131][' name '] Print (id_db[3713131131]) print ([Id_db.fromkeys], ' DDD ') print (Id_db.setdefault (3713131131), "haha") # Returns None#for key in id_db:#    print (Key,id_db[key]) 
 If a key value does not exist

The Python dictionary contains the following built-in functions:
1, CMP (Dict1, DICT2): compare two dictionary elements.
2. Len (dict): Calculates the number of dictionary elements, that is, the total number of keys.
3, str (dict): output dictionary printable string representation.
4. Type (variable): Returns the type of the input variable and returns the dictionary type if the variable is a dictionary.

python dictionary contains the following built-in methods:
1, Radiansdict.clear (): Delete all elements in the dictionary
2, Radiansdict.copy (): Returns a shallow copy of a dictionary
3, Radiansdict.fromkeys (): Creates a new dictionary with the key of the dictionary in sequence seq, Val is the initial value corresponding to all keys of the dictionary
4, Radiansdict.get (Key, Default=none): Returns the value of the specified key, If the value does not return the default value in the dictionary
5, Radiansdict.has_key (key): Returns False if the key is true in the dictionary dict
6, Radiansdict.items () : Returns a traversed (key, value) array of tuples as a list
7, Radiansdict.keys (): Returns a dictionary of all keys in a list
8, Radiansdict.setdefault (Key, Default=none): and get () Similarly, if the key does not already exist in the dictionary, the key is added and the value is set to default
9, Radiansdict.update (DICT2): Updates the dictionary dict2 key/value pairs to dict
10, Radiansdict.values (): Returns all values in the dictionary as a list

#!/usr/bin/python3#-*- coding:utf-8 -*-#写一个购物小程序 # User starts by entering the Payroll # User starts the program and prints the Product list # allows the user to choose to buy the product # allows users to constantly buy a variety of products # Check whether the balance is sufficient at the time of purchase, if enough direct debit, otherwise insufficient printing balance # allows the user to exit the program voluntarily, print the purchased list on exit # to determine whether the number Gongzi = input ("Please enter the salary: ") if  Gongzi.isdigit ():     gongzi = int (Gongzi) else:    exit (" Please enter the number ") #使用center   input Information Center welcome_msg =  ' welcome to shopping mall '. Center (50, '-') Print (welcome_msg) #商品列表product_list  = [     (' iphone ', 5888),      (' Mac air ', 8888),     (' Mar pro ', 9008),     (' Xiaomi2 ', ,     (' coffic ', '),] #定义一个列表shop_car  = [] #标志位, exiting the while loop exit_flag =  falsewhile exit_flag is not true:    print ("Product list"). Center (+, '-'))     for item in enumerate (product_list):         index = item[0]        p_name = item[1][0]         p_price = item[1][1]         print (Index,p_name,p_price)     user_choice = input ("[Q= exit, c= selection] Please select Product  : ")     if user_choice.isdigit (): #肯定是选择商品          user_choice = int (User_choice)         if  User_choice <  len (product_list):             p_item = product_list[user_choice]             if p_item[1] <= gongzi:    #买得起                  shop_car.append (P_item)  # Add to Cart &NBSP;&NBSP;&NBSP;&NBSP;&Nbsp;           gongzi -= p_item[1]    #减钱                 print ("Add  [%s]  to your cart, your balance is  \033[31;1m[%s]"  % (P_item,gongzi)              else:                 print ("Your balance is [%s], cannot buy"  %gongzi)     else:         if  user_choice ==  ' Q '  or user_choice  ==  ' Quit ':              print (" The products you purchased are as follows ". Center (+, ' * '))              for  item in shop_car:                  print (item)              print ("END". Center (40, ' * '))              print ("Your balance is \033[31;1m[%s]"  %gongzi)              exit_flag =  true

This article is from "Hao son of ▁ Yun's finger licking" blog, please be sure to keep this source http://chenhao6.blog.51cto.com/6228054/1864291

Python Learning Note 2