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,id (L2)) L1.append ('a')Print(L1,L2) l1[2].append ('a')Print(L1,L2)Print(ID (l1[2]))Print(ID (l2[2]))###################[1, 2, [4, 5, 6], 3] 1921627608072[1, 2, [4, 5, 6], 3] 1921628470728[1, 2, [4, 5, 6], 3,'a'] [1,

'].append (i)Panax Notoginseng Else: -dic['K2'].append (i)defaultdictFour, can be named tuple (namedtuple)Depending on nametuple, you can create a type that contains all the functions of a tuple and other features.1 #T = (one, one, one, one)2 #name adddress gender Email similar to coordinates3 #t.name equivalent to t[0]4 5 ImportCollections6 7 #create a class that works like Defaultdict8Mytupleclass = C

to multiple elements.Assuming that the function object returns True, the elements of that secondary are stored in the returned table. Filter filters the data by a function that is read in.Such as:Def fun3 (a): if a >: return True else: return falseprint filter (FUN3, [10,20,100,110])Output:[+]Four, reduce () functionThe first parameter of the reduce function is also a function, but there is a requirement that the function itself can receive two of the parameters.Like what:Pr

above, the data is not accurate.If you want to avoid this situation, just use get and CAS, such as:#!/usr/bin/env python#-*-Coding:utf-8-*-#Author: Haifeng DiImport MemcacheMC = Memcache. Client ([' 192.168.10.128:12000 '], debug=true)v = mc.gets (' Product_count ')Print (v)#如果有人在gets之后和cas之前修改了product_count, the following setting will fail to throw an exception to avoid output of abnormal dataV1 = Mc.cas (' Product_count ', "899")Print (v1)#结果:899Tr

CentOS 7 has a built-in Python version of 2.x, and many programs rely on the 2.x version, which will invalidate some of the Python scripts.For example: Yum, Firewall-cmd, Firewall-config, and so on.If you encounter a similar reference error, this is basically the cause:

often used in counting loops, these "infinite" loops are not necessarily bad, and many of the client/server systems of a communications Server are working through it.Sum=0i=0while (iExecution results are4950Four, for loop statementsFor Loop statement format:For iteration variable in range (Start,end,step):Loop bodyFor iteration variable in xrange (start,end,step):Loop bodyFor Each loop, the iteration variable is set to iterate over the current element of the object (sequence, iterator, or other

Objective1.python Environment 2.72.threading module System comes withSingle Thread1. The usual code is executed in order, like eating hot pot and humming the two behavioral events, defined as two functions, the implementation of the time is to eat hot pot and then hum a tune, this is a single-threaded behavior.# coding:utf-8import timedef chi(): print("%s 吃火锅开始：" % time.ctime()) time.sleep(1) print("%s 吃火锅结束--" % time.ctime())def heng(): p

first. >>> import JSON >> > Dordereddict ([( " foo , 1), (" bar , 2), (" spam , 3), ( ' grok , 4)]) >>> Json.dumps (d) " {" foo ": 1," Bar ": 2," Spam ": 3," Grok ": 4} >>> Add: Ordereddict internally maintains a doubly linked list, which arranges the position of the keys according to the order in which they are added. The first newly added element is placed at the end of the list, and subs

int (integral type)The number of integers is 32 bits and the value range is -2**31~2**31-1, which is -2147483648~2147483648Long (integer)Unlike the C language, Python's long integers do not refer to the positioning width, i.e. python length does not limit the size of long integer values,But in fact, because of the limited machine memory, we use a long integer val

joined, one at a time.Add the Leader's name to the group Leader's notesAsk you to print a person every other person>>> name = [' Alex ', ' xiaoming ', ' Rain ', ' Eric ', ' Monica ', ' Fiona ']>>> Name.insert ( -1, "xiaochuan")>>> Name.insert (5, "dachuan")>>> name[3:8][' Eric ', ' Monica ', ' Dachuan ', ' Xiaochuan ', ' Fiona ']>>> Name.remove ("Fiona")>>> Name[' Alex ', ' xiaoming ', ' Rain ', ' Eric ', ' Monica ', ' Dachuan ', ' Fiona ']>>> del name[4:6]>>> Print (name[::

I. digress Previously, I vowed that this series of notes would be completed in May, but now it is almost impossible. Why is this happening? I have reflected on the following: 1. The learning route is not firm: Python, Django, mysql, and jquery later, disrupt the original plan. 2. Unclear objectives: I don't know how much I want to achieve, what functions I want to implement, and so on, which leads to poor b

CollectionYou can create a collection with Set (), or directly with {}Set_a = Set ([1,2,3,4,5]) Set_b = {1,3,5,7,9}print (set_a) print (set_b) print (Type (set_a), type (set_b))The collection also has a variety of operations, which can be recorded in several symbols. Check it out when you get to the other.Set_a = Set ([1,2,3,4,5]) Set_b = {1,3,5,7,9}print (set_a | set_b) # and set print (Set_a set_b) # intersection print (set_a ^ set_b) # Symmetric difference print (set_a-set_b) # difference se

1. Scope of variables(1) Variables defined within a function include arguments, function only within the scope of the functions, and local variables are similar.(2) Global variables, inside functions can be called outside the function, even if the variable is defined after the function.Note: Local variables and global variables are defined in the same way as other languages.If you modify a global variable within a function Zjh,

Evaluates any string as a Python expression:Eval () Method:Eval (source[, globals[, locals]), valueEvaluate the source in the context of globals and locals.The source may be a string representing a Python expressionOr a code object as returned by compile ().The globals must be a dictionary and locals can is any mapping,Defaulting to the current globals and locals.If only globals are given, locals defaults t

, world' >>>. lower () # all lower case 'hello, world' >>>. capitalize () # upper-case letters, and lower-case 'hello, wold' >>>. istitle () # whether the first letter is in uppercase. If True is returned, FalseTrue is not returned. >>> a 'hello, wold' >>> B = "hellow, world" >>> B. istitle () # returns falseFalse if the first letter is not in upper case>. islower () # whether all strings are in lowercase. If true is returned, falseFalse is not returned. >>> B. islower () True It seems that this

Python Study Notes 2: python Study Notes Chapter 4 for and while Loops 1. for is faster than while. The author of the python learning manual has been restarting to emphasize this. 2. A lot of for usage A. for x in list:, similar to foreach in C #, but the modification to x c

output four: ") a = [[1, 2], [3, 4]] B = a[:] Validate (A, B) answer4 () def ANSWER5 (): "" "Deep copy Copy.deepcopy:return:" "" Print ("\ n output five:") a = [[1, 2], [3, 4]] B = Copy.dee Pcopy (a) validate (a, B) Answer5 () def ANSWER6 (): "" "Shallow copy copy.copy, with Answer3:return:" "" Print ("\ n output six:") A = [[1, 2], [3, 4]] B = copy.copy (

the matched string at the index position(expand) (template)Substituting the matched grouping into the template and then returns. The template can be grouped using \id or \gm = Re.search (R ' (\w+)! (\w+) (\w+) ', ' hman! How finny! ') #将匹配的结果带入 print M.expand (R ' resut:\3 \2 \1 ')>>> Resut:finny How HMan(groupdict) ([Default=none])The function is to assign all the groupings that match to and specify the alias, alias as key, match the string to value

Python advanced (8): common module 2 + exception handling, python advanced Some time ago I talked about a lot of modules. I didn't talk about objects at the time. I didn't talk about them today. I also talked about exception handling. I. hashlib Module Python hashlib provides common digest algorithms, such as MD5 and

Practical drills of "Python efficient development practices"-application Building 2 and python efficient development practices To develop practical applications that conform to the MVC Architecture in the project, you need to create a Django application in the project. Each Django project can contain multiple Django applications. The syntax for creating an applic