python dictionary of dictionaries

.count (' a ')) #统计aPrint (L2.index (' A ')) # Find the index of aL2.insert (2, ' Insert ') # InsertL2.remove (' a ') #删除L2.sort () # Sort, mainly alphabeticallyL2.clear () # Empty AllFor i in L2: # Loop Traversal, note to add : Print (i)2, Dictionary# Dictionary similar to the MAP in Java has key and valuedic={' s1 ': ' Dong Jintao ',' s2 ': ' Male ',' S3 ': ' A ',}dic[' S4 ']= ' Han ' # adddic[' S3 '

','Egon','Zhangquan Egg','li Tie Egg','Oldboy'}stus_python={'li er ya','wxx','Liudehua','Alex','Egon'enroll both Linux and Python students: intersectionPrint(Stus_linux Stus_python)Print(Stus_linux.intersection (Stus_python)) All students: the collectionPrint(Stus_linux |Stus_python)Print(Stus_linux.union (Stus_python)) only registered Linux, not registered python: Difference setPrint(Stus_linux-Stus_python

This article focuses on the use of the clear () method of manipulating dictionaries in Python, which is the basics of getting started with python, and needs friends to refer to the The clear () method deletes all items in the dictionary (empty the dictionary) Grammar The

# dictionaryA = None # none = nullb = False # BooleanC, D = A, 10.6 # int FloatE = ' ASDD ' # strf = [' s ', ' E '] # list, array, can be added and censoredG = (' A ', ' s ', ' F ') # tuple (tuple), can only be checked# dictionaryT = {# Key: Value"' :',"' : '}# dictionary# dict Key:value key is unique, unorderedH={' s ': 12,' F ': False,2: ' d ',' R ': ' t ', ' SD ': [' GF ',' RT ',' ew '],' RT ': (' RTE ',' EWR '),' ru ': {' rty ': ' FGHG ',' dfs ':

Functions and descriptions Example 1 Len (dict)Calculates the number of dictionary elements, that is, the total number of keys. >>>={' Name ':' Runoob ',' age ':7,' Class ':' First '}>>> len(dict)3 2 STR (DICT)The output dictionary, expressed as a printable string. >>>={' Name ':' Runoob ',' age ':7,' Class ':' First '}>>> str(dict)"{' Name ': '

The dictionary is the only built-in mapping type in Python.Create dictionary phonebook = {' Alice ': ' 2341 ', ' Beth ': ' 9102 '}You can use Dict to build a dictionary from a sequence of other mappings or key-value pairs. Key value parameter to create a dictionary.The number of items in Len (d) d. D[K] Returns the value associated to the key, d[k] = v assigns th

Custom Create ordered dictionary classesDict's __getitem__ method is somewhat different and wants to use a custom __getitem__ method to display the subscript of the query key;#/usr/bin/env python3#-*-coding:utf-8-*-# author:zshaoxclass mydict (dict): li = [] #定义列表用于有序的排列key值 def __setitem__ (self, Key, value): #自定义__setitem__方法, extending the parent class method Self.li.append (key) #将对象的key added to the list super (mydict, SE

', ' age ', ' sex '],22222)Print (DIC)Effect: {' name ': 22222, ' age ': 22222, ' Sex ': 22222}-----------------------------------------------Goods = [{"Name": "Computer", "Price": 1999}, {"name": "Mouse", "Price": ten}, {"name": "Yacht", "Price": $}, {"Name" : "Beauty", "Price": 998},] Goods[0].setdefault (' AA ', []). Append (' one ') print (goods) effect: [{' name ': ' Computer ', ' Price ': 1999, ' AA ': [ ' One '}, {' name ': ' Mouse ', ' Price ': ten}, {' name ': ' Yacht ', ' Price ': $},

in a dictionaryThe Dict () constructor can create a dictionary directly from the key-value pairDict ([' Tim ', 123), (' Tiny ', 234)]) >>>{' Tiny ': 234, ' Tim ': 123}Derivation creates a dictionary:{d2:d2+ ' @main. com ' for D2 in List (D.keys ()}}>>>{' Jack ': ' [email protected] ', ' Tom ': ' [email protected] '}Exercise: A key-value pair in a circular output dictionary:For Name,email in D.items ():Prin

First, define a dictionaryCreated with {}, each key value in the dictionary is key=>value with a colon : split, separated by commas , between each key-value pair shenyang={' name ': ' Shenyang ', ' age ': ' Sex ': ' Male ', ' addr ': ' Tian Tong Yuan ', ' qq ': ' 19322 ', ' email ': ' [email protected] 'Second, the judgmentNon-NULL is true, not 0 is trueFor example: (if the contents of the E variable have the data true, the empty print is false)E= "If

pairDict ([' Tim ', 123), (' Tiny ', 234)]) >>>{' Tiny ': 234, ' Tim ': 123}Derivation creates a dictionary:{d2:d2+ ' @main. com ' for D2 in List (D.keys ()}}>>>{' Jack ': ' [email protected] ', ' Tom ': ' [email protected] '}Exercise: A key-value pair in a circular output dictionary:For Name,email in D.items ():Print (Name,email)4. CollectionEmpty collection: A = set () ※ to create an empty collection, you must use Set ()Demonstrate:Basket = {' Appl

Dictionaries The dictionary can be understood as an upgraded version of the listList list={"Dandan", "Zhangsan", "Wangwu"} Dictionary dic={' name ': ' Faint ', ' sex ': ' Man ', ' professional ': ' Computer Science and Technology '} If you need to modify the "Zhangsan", you need to find its subscript, and the dictionary