coursera full stack web development review

SetDefine set ([1,2,3,4]){1,2,3,4}Key values are not repeatableTernary operatorsif Else value2Depth copyImport"123"# shallow copy # deep copy Summarize:1. The depth copy does not copy the STR and the numbers, using the same area of memory.2. For list, dict,tuple copy, shallow copy only copy first layer. Deep copy copies all layers, and the last layer does not copy when it encounters a string or a number.Function programmingPython Full

1. Parameters of the function, reference 2. Lambda expression 3. Python's built-in function 4. Recursive 5. File operations1. Open FileOpen (file name/file path, open mode, encoding)Open mode: R read-only mode, default is read-onlyW write mode, unreadable; Create a file that does not exist; Clears the contents of the file if it existsX write mode, unreadable, file does not exist, create one, file exists, errorA append mode. The file does not exist, a file is created, and if the file exists, it i

return b5 6 ret = func () 2. function can not return value1 def func1 (): 2 A = 1113 b = [4]ret = func1 ()print (ret)6 # function can have no return value 7# when no return is written, the default return value of a function is ' None '3.1 def Func2 (): 2 A = 1113 b = [5]4 return# ret = FUNC2 () 6# print (ret)7# When you write only one return, the return value of the function is NoneNone4.def func3 (): = 111 = [+= ]return None# ret = func3 ()# thereturn

the name of the built-in namespace are globally scoped and can be referenced anywhere in the entire file, effectively globallyLocal scope: Local namespace, only valid locally3, stand in the global viewWhen using a name, if it is global, use the globalIf the global is not, use the built-in4, why should have scopeFor variables within a function do not affect the global5.PassFour, closed packet functionClosures: 1. Closed: Internal function2. Package: Contains a reference to a variable in the scop

') F.writelines (['1111\n','2222\n','3333\n'] # Writes a string list to a file f.write ('aaaaa\nbbbb\nccccc\n')Summary:W: Write-only mode1. When the file is present, empty2. Create an empty document when the file does not existAppend Mode (a)#A: Append write mode only#Note:#Create an empty file when the file does not exist#when the file exists, the cursor runs directly to the end of the fileF=open ('Access.log', mode='a', encoding='Utf-8')#print (f.writable ())#f.readlines () #报错F.write ('555555

the end condition.Summarize:1. Recursion must have a definite end condition2. The size of the problem should be reduced every time the next recursion is entered3. No tail-recursive optimizations in Pythonanonymous functionsWhat is anonymous function keyword lambdaanonymity means no name . def func (x,y,z=1): return x+y+z anonymous lambda# has the same scope as a function , but anonymity means that the reference count is 0 and is used once to release, unless it has a name func=Lambda x,y,z=1:

* Specifies the length, from the beginning of the truncation, do not specify the length, from the current position to the end of all removedF.writable ()#determine if it can be writtenIii. Modification of documentsHere's a simple way to implement a file modification:#File ModificationImprot os #这里导入了os模块去改文件名f_name='C:\\users\\administrator\\desktop\\3.txt'F_new_name='%s.new'%F_nameold_str='Xinjiang'New_str='Beijing BJ'F= Open (File=f_name, mode='R', encoding='GBK') F_new= Open (File=f_new_name

Dictation Code:The conversion relationship between BIT,BYTES,KB,MB,GB,TB.UNICODE,UTF-8,GBK, each encoded in English, Chinese, respectively, in a few bytes.TrueFalse736303TrueTrue0304Cannot start with special symbols, _ or letters, concise and meaningful, avoid keywordsString strIf condition:ResultsElseResultsWhile condition:ResultsCount = 0sum = 0 While Count Count + = 1if count== 88:continueElif count% 2 = = 1:Sum + = CountElse:Sum-= CountPrint (sum)Count = 3 While count > 0:Username = input (

While loopWhy would there be loops like this statement?To give a simple example: we want to calculate the number of even numbers within 0-100, and this time we need to loop this statementThen one might say, "What 0+2+4+.......+98 can be calculated?"Suddenly our condition changed: Calculate the number of even numbers within 0-10000000 andIt can be imagined that this is how a workload, the cycle is just to solve this problem.Figure:The representation of a while loop in Python is like.Grammatical f

type base data type:String:Number:Number.max_value,number.min_value.Nan is not equal to NanIsNaN (' Test ') #trueInfinityBoolean:Null:Undefined:Reference data type:Array: ArraysString:Date:Object:4) Data type conversion　　　　　　　　 Number + String : Number converted to string Number + Boolean: True converts to 1,false to 0 String + Boolean value : Boolean converted to string true or False Convert to String: toString () Convert

27. File A.txt content: Each line content is the product name, the price, the number.Apple 10 3Tesla 100000 1MAC 3000 2Lenovo 30000 3Chicken 10 3Through the code, build it into this type of data:[{' name ': ' Apple ', ' price ': Ten, ' Amount ': 3},{' name ': ' Tesla ', ' price ': 1000000, ' Amount ': 1} ...] and calculate the total price. "ImportOs,relst=[]with Open ('C','R', encoding='Utf-8') as F1:dic= {} forLineinchF1:li= Re.sub (r'\s{1,}',',', line). Strip (',') dic['name'],dic[' Price'

20. Determine whether a number is a narcissus number, the number of daffodils is a three-digit, three-digit each of the three-square and also equal to this number. That number is a number of daffodils, for example: 153 = 1**3 + 5**3 + 3**3num = input (" Please enter a three-digit number:"= Int (num[0]) * * 3 + int (num[1]) * * 3 + int (num[2]) **3if int (num) = = s :print(" Narcissus number ")Else : Print (" no ")Python3.6 full