coursera full stack web development review

#map (a method (typically a lambda expression, or a custom method) that iterates over an object (which can be traversed with a for loop).#处理序列中的每个元素, the result is a list with the same number of elements and position as the original num=[1,2,34,223,1,3 " def C (d): return d**2def text (list,h): Tet =[] for e in list:res =return tet print (text (Num,lambda x:x**2 print (List ( Map (lambda x:x+1,num))) Print (List (map (c,num))) #filter (a method (typically a lambda expression or

. First create a file B.txt, write the content, read the contents of the file.Since the file is related to Chinese, the code here is Utf-8With open (' B.txt ', ' R ', encoding= "Utf-8") as F: For line in F: #去除字符串左右2边的空格 line = Line.strip () # Determine if the line is empty if Len = = 0: continue #打印文件内容 Print2. Each row determines if Alex exists, and if so, replace it with the Replace () methodWith open (' B.txt ', ' R ', encoding= "Utf-8"

that the brackets should be changed to curly braces. Direct illustrative examplesEg: uppercase and lowercase key mergingMcase = {'a': 10,'b': 34,'A': 7,'Z': 3}mcase_frequency={k.lower (): Mcase.get (K.lower (), 0)+Mcase.get (K.upper (), 0) forKinchMcase.keys ()ifK.lower ()inch['a','b']}Printmcase_frequency#Output Results{' A ': +, ' B ':Eg: Quick change of key and valueMcase = {'a'b': in Mcase.items ()}print mcase_frequency# Output Results {ten: ' A ', ' C ': ' B '}Set Deduction formulais simi

;sencond ') yield 2 print (' ===== >third ') yield 3obj=chicken () print (obj) #Second, the generator is an iteratorThe generator is essentially an iterator, which means that the generator's gameplay is actually an iterator.Obj.__iter__obj.__next__#2, so the generator is an iterator, so you can take this value res=next (obj) print (res)Mimic range () functiondef my_range (start,stop,step=1): While start For item in My_Range (1,10,2): print (item)# Result: 1,3,5,7,9Iii. conclusion

entire event (follow the top-to-bottom row-by-line execution).Local scope:Can be used inside a function.Scope namespaces:1. Global scope: global namespace + built-in namespaces2. Local scope: local namespacesFunctions: Globals () and locals ()Globals (): variable and function information used to view global scopeslocals (): used to view the contents of a local scope (which layer it depends on, which layer of variables and function information)3. Nesting of functions1. Just meet () is a function

characters　　　　test='Alex'v=test.strip ('A')Print (v)Output: Lex1.5 Upper ()Convert lowercase letters to uppercase　　test='Alex'v=test.upper ()print(v)Output: ALEX1.6 Lower ()Convert uppercase letters to lowercase　　test='ALEX'v=test.lower ()print(v)Output: Alex2. Special usage2.1 Gets a value from a string according to the index　　test='Alex'v=test[0]print(v)-------- A2.2 Gets a value of a string based on the range　　test='Alex'v=test[0:3]print(v)------Ale The value that you want to get is determi

RecursiveContinue running functions within the function, knowing that a goal is reached and the final return value.Characteristics of recursion:1. The function must have a definite end condition2. Without entering a recursion, the problem that needs to be addressed should be reduced3. Recursive efficiency is low, need to prevent memory overflowClass Exercises　1. Ask the way　　#Ask the way, there are several people on the road, ask if one of them knows where the place is.s1=['Alex','Xuzheng','Xiao

, Name, age):self.name = nameself.age = Agedef func (self):print (' in Func ')content=input ("if Hasattr (a,content): # equivalent if hasattr (A, "string")Print (GetAttr (a,content)) Print (GetAttr (A, "func")) # Print (GetAttr (A, "func") (one)) # in Func none (default returns None)Print (GetAttr (A, "job")) # Student Print (GetAttr (A, "Job1", "false")) # FalsePrint (GetAttr (A, "Job1")) # Error type object ' A ' has no attribute ' job1 '(3). Examples of other modulesImport Old_boyobject=getat

Split ()　　　　A=re.split ('ab','abc')Print (a)--[' ', ' C ']First split the AB, corresponding to match ab left nothing, so get the empty string, and ' C ', then AB again with C to match, no match on, output C2.11 Sub () Replace　　　　A=re.sub ('\d','abc','fhsdk3fhsdk' )print(a)--fhsdkabcfhsdkA total of three parameters, the first is the way to match, the second is after the replacement of it, the third is to find the object, and then replace2.12compile () compilationMake the rules first, then you c

Exercises:Import RequestsImport reImport JSONdef getpage (URL):response=requests.get (URL)return Response.textdef parsepage (s): com=re.compile (' '. *?Ret=com.finditer (s)For i in RET:Yield {"id": I.group ("id"),"title": I.group ("title"),"Rating_num": I.group ("Rating_num"),"Comment_num": I.group ("Comment_num"), }def main (num):url= ' https://movie.douban.com/top250?start=%sfilter= '%numresponse_html=getpage (URL)ret=parsepage (response_html)print (ret)F=open ("Move_info7", "a", en

]\D{16}[0-9X]|^[1-9]\D{14}(vi) the signifier \1. In regular expressions, there are a lot of special meanings are metacharacters, such as \d and \s, etc.If you want to match the normal "\d" instead of "number", you need to escape the "\" to become ' \ \ '2. So if the match "\d", the string to write ' \\d ', then the regular will be written in "\\\\d", so it is too troublesome.At this point we use the concept of R ' \d ', where the regular is R ' \\d ' ("R" means to cancel all escapes)(vii) Greedy