full stack development book

collection (set)Collection, save a lot of data, can not repeat features: unordered, non-repeatable, content can be hashed, itself is not hash k = fRozenset (collection): It's going to be a hash.Increase:S.add (content) s.update ("content"): Iterative additionsDelete:S.pop (): Randomly deletes one and returns the deletion of that content s.remove (' specified element '): Delete the specified element, if not present will error S.clear (): Empty collection, if print out empty collection will show s

longer locally created. ? is the direct cause of the global aA=28Print (a)Func ()Print (a)# for variable data types you can go directly into the. But you can't change the address. Say it. Cannot assign a valueLST = ["Twist Vine", "Carina Lau", "James"]def func ():Lst.append ("? and") # can be accessed directly into the variable data type. But you can't change the address. Say it. Cannot assign a valuePrint (LST)Func ()Print (LST)2.nonlocal table? In the local field, adjust? Variable in the clas

corresponding to the same value, forming a dictionaryinfo='Alex's1={}v2=s1.fromkeys (info,222)print (v2) {'a'l'e ' ' x ': 222}4.5 get, returns value according to Key, if none is returned, the none can be modified　　　　info={'Alex': 123, 'a':'nishishei' ,'v': 555}#info= ' Alex 'v2= Info.get (567,222)print(v2)------222Because there is no key567, so return parameter, 2224.6 Pop (key, return default value)If there is no key, the default value is returnedIf there is, then delete and get4.7 Popitem ()R

]def __len__(self):returnLen (self.__cards) def __getitem__(self, item):returnSelf.__cards[item]def __setitem__(self, Key, value): Self.__cards[Key] =valuedef __delitem__(self, key):delSelf.__cards[Key]deck=Franchdeck ()Print(Deck.__dict__)Print(Deck[0]) random.shuffle (deck)Print(Deck.__dict__)Print(Random.choice (deck))examples of shuffling and drawing cards4. Exception Handling#try except#try except Else#try except else finally#try finally# Assert 1=2# raise actively throws an exception# C

{Font-size:20px; color:red; } /* Select the last element */Div ul Li:last-child{Font-size:20px; Color:yellow; } /* Select the currently specified element value starting at 1 */Div ul Li:nth-child (3) {font-size:30px; Color:purple; } /*n means check all, this must be N, from 0 to 0 is not selected */Div ul Li:nth-Child (n) {font-size:40px; color:red; } /* even * *Div ul Li:nth-Child (2n) {font-size:50px; Color:

19. Kill the host. The following information on the host revenue, as required, to complete the appropriate operation:(1) Calculate the average return value of the anchorsum = 0 for in zhubo.values (): + =Iprint(round (Sum/len ( Zhubo)))(2) to kill the host with less than average income dic1={} # Create an empty dictionary to store people less than the average for i,j in zhubo.items (): # loop anchor dictionary if j# below the mean condition dic1[i]=j # People below the mean a

24. File A1.txt content (note that the spaces in each line are not the same, you need to handle the space)Number of department number average age remark1 Python 30 26 single Dog2 Linux 26 30 no objects3 Operations Department 20 24 more girlsThrough the code, build it into this type of data:Li = []ImportRewith Open ('T4','R', encoding='Utf-8') as F:first= Re.sub (r"\s{2,}"," ", F.readline (). Strip ()) first= First.split (' ') #print (first) forIinchf.readlines (): DiC={} i= Re.sub (r"\s{2

Tag: Col key value to RET UNC data type call int return python7. This function receives only one parameter and this parameter must be a list data type, and the functionality that is done is to return a dictionary to the caller, the dictionary's key value pair for this list index and the corresponding element. For example, the incoming list is: [11,22,33] Returns a dictionary of {0:11,1:22,2:33}.L2 = [11,22,33]def Func8 (L1): = {} for in Range ( Len (L1)): = l1[i] return dicpri

There are two basic output statements in PHP, Echo and printWhat's the difference between these two things?echo can output one or more characters at a time:Echo "This is a", "string,", "used", "multiple", "parameter." ";Like this, there is no problem with the output.The result of the output is: This is a string that uses more than one parameterThen echo's output is not wrapped, and if you need to wrap it, you can add it later Echo "This is a", "string,", "used", "multiple", "parameter." You can

can improve compatibility3.1 Json.dumps ()　　　　Import jsondic={'Alex':'+ '# Note the JSON-type string , all in double quotes, at which point the single quote a=json.dumps (DIC)print(a) {"Alex " " - "} # automatically outputs into double quotes, and is compatible with each platformThere is a shortcut, Json.dump (' Sjah ', f)The former is the data that needs to be written, and the latter is the file to be written, which is relatively fast3.2 Json.loads ()Take the JSON type string out, note that i

" This time triggered the new action, we want to record this behavior, if it is only recorded "Gxqsd a new role" that obviously he is a bit like the message log, but it can not be used for historical records. So the most important thing to do as a behavior log is to record the changes in the data. So there's a new role for GXQSD, and the right approach should be to store the new role entity information.Next, a simple diagram is used to describe the relationship between database tables.We define

Tag:slowfriend key value gitsub asc Replace string dea$$ What to learn today: 1. Basic data type initial: int: for calculation. STR: Used to store a small amount of data such as: ' Alex ', ' 123 ': Bool:true, Falselist: (list): The inside can put a variety of data, can store a lot of data, easy to manipulate the format of the list is: [' name ', true,[] ...] Tuple: (tuples, also called read-only lists) the format of tuple is: (' name ', true,[] ... Dict: (dictionary): stores a large number of re

First, the basic knowledge There are two ways to run Python: The first is run through interactive operation, through "start", "All Programs", "python3.x", "IDLE". The second is that we write the Python file double-click Run. Help system for Python () We enter help () in interactive mode, enter the function name you want to query. If you want to exit from the help mode into interactive mode, simply type in assist () after help>.II. Basic data typesThird,

list be traversed with the __next__ methodL2 = [1, 2, 3, 4, 5, 6, 7, 8]l2_obj = l2.__iter__ () #1. Convert an iterative object to an iterator while True: try: i = l2_obj.__next__ () #内部使用__n Ext__ Method Value print (i) except Exception: #运用了异常处理去处理报错 break Try inside the code, there is an error, will not prompt red textException can receive all the error, indicating the error when, how to deal with, here directly use Breck jump out of the loopInterview questions:Use

string (for example, S=u ' forest '), it requests a new memory address and then stores the ' Forest ' in Unicode format in the new memory space, so s can only encode and cannot be decodeS=u ' Forest 'Print repr (s) #u ' \u6797 'Print type (s) ## s.decode (' Utf-8 ') #报错, S is Unicode, so you can only encodeS.encode (' Utf-8 ')For data in Unicode format, no matter how it is printed, it is not garbled.The string in python3 and the U ' string ' in Python2 are Unicode, so printing is not garbled an

(count)Count+=1Topic FiveRes=0Count=1While Count If count%2 = = 0:Res-=countElseRes+=countCount+=1Print (RES)Topic SixCount=0While Count Name=input (' Please enter user name: ')Password=input (' Please enter password: ')If name = = ' Egon ' and password = = ' 123 ':Print (' Login success ')BreakElsePrint (' User name or password error ')Count+=1Topic Sevenage_of_oldboy=73Count=0While Count Guess=int (Input (' >>: '))If guess = = Age_of_oldboy:Print (' You Got it ')BreakCount+=1Topic Eightage_of

, **kwargs) return obj# object parentheses will execute __call__ method class Foo (MyType (' Zcc '), (object,) , {})): #MyType (' Zcc ', (object,), {}) is equivalent to class ZCC (object):p, that is, creating a Zcc class user = ' Haiyan ' age = 18obj = Foo () # Way Three Class MyType (type): def __init__ (self, *args, **kwargs): print ("SSSs") super (MyType, self). __init__ (*args, **kwargs) Def __call__ (CLS, *args, **kwargs): v = dir (cls) obj = Super (MyType,

. Foo () () #也可以这样表示6.__len__7.__hash__Class Foo:def __hash__ (self):Print (' aaaaaaaaaa ')return Hash (self.name)# print (' AAAS ')f = Foo ()F.name = ' Egon 'Print (hash (f)) #hash方法是可以重写的8.__eq__Class A:def __eq__ (self, Other):Return TrueA = A ()b = A ()Print (a==b) #不加方法的时候返回的是False, adding a __eq__ method returns a true# ' = = ' inside called the __eq__ methodPrint (A is B)A question of a face# Card game from collections Import Namedtuplecard = Namedtuple (' Card ', [' rank ', ' suit ']) #

)) print ('%s Is Piao end '%self.name) if __name__ = = ' __main__ ': p1 = Piao (' alex ') P2 = Piao ( ' Wupeiqi ') p3 = Piao (' Yuanhao ') P1.start () P2.start () p3.start () print (' main process ', Os.getpid ())Getppid () Parent process IDGetpid () #当前进程idFive, multi-process implementation socket concurrency#服务端from Socket Import *from multiprocessing Import processs = socket (af_inet,sock_stream) s.setsockopt (sol_socket,so_ reuseaddr,1) S.bind ((' 127.0.0.1 ', 808

Whlie Condition # (when the condition is true) #break force terminate loop: #continue jump out of the current loop:Print ("num") # (Output num)Cases:Output 1 to 100 evennum = 1Whlie Num If num%2 = = 0:Print ("num")Num+=1　　Cases:Yonghu = 1093166587Mima = 123456789While True:AA = Int (input ("User name:"))bb = Int (Input ("Password:"))if AA = = Yonghu:Print ("Welcome to this page")Break # break terminates the loop;ElsePrint ("Input error")Print ("")Example: #嵌套循环:height = Int (input ("Height:"))wi