Python Basics-exceptions, objects, and iterators

• Exception handling
• Object oriented
• Iterators and generators

Python Exception handling

• The following code triggers a filenotfounderror

>>> Open ("Notexist.txt") Traceback (most recent call last):  File "<stdin>", line 1, in <module> Filenotfounderror: [Errno 2] No such file or directory: ' Notexist.txt '

• Throw exception

>>> Raise Filenotfounderror

• Exception type

• Catching exceptions using Try,except,finally,else

Try:  open (r "C:\Users\kingsoft\Desktop\notexist.txt") except Filenotfounderror as E:  print ("File not exist ... ") except (name1,name2):  print (" IO error is true ... ") Else:  print (" file exist.. ") Finally:  print ("Always do ...")

　　

Python Object-oriented

Python is completely object-oriented, and everything in Python is an object, including variables, functions, and so on.

• Defining an Object

Class MyException ():p

• Self and Init methods

Class person ():d EF __init__ (Self, name): Self.name = Namedef sayname (self):p rint Self.namem = person ("Joe") print ( M.sayname ())

• Examples of district classifications and classes

Class person ():d EF __init__ (Self, name): Self.name = Nameperson.name = Namedef sayname (self):p rint ("MyName is:" + Self.nam e) Print ("Myexceptionname is:" + person.name) def changeothername (self, name):P erson.name = Namedef __del__ (self):p rint ( Self.name + "is Gone") m = Person ("Joe") M.sayname () print ("M.name:" + m.name) m.test= "TT" Print (m.test) j = Person ("Jason") J . Sayname () j.changeothername (j.name) m.sayname ()

• Class inheritance, polymorphism, and encapsulation concepts

Generators and iterators

• The _iter_ method returns an iterator that refers to an object with the next method

Class Fibs (object): "" "DocString for Fibs" "" "Def __init__ (Self, max): Self.max = MAXSELF.A = 0self.b = 1def __next__ (self): fi b = Self.aif fib > self.max:raise stopiterationself.a, self.b = self.b, SELF.A + Self.breturn fib# return iterator def __iter__ (sel f): Return SELFFIB = Fibs (+) for F in Fib:print (F, end= "")

• Object Iterable and iterators can be iterated iterator
• Generator, the generator quickly generates iterators through yield statements, making the function a generator

#斐波那契数列def getfibs (max): a = 0b = 1while A < Max:a, b= b, a+bvalue = Ayield Valueprint (getfibs (+)) for I in Getfibs (10 XX):p rint (i)

• Simple Understanding Generator

Def gen (): Yield "Hello" yield "how" yield "is" yield "you" for I in Gen ():p rint (i)

　　

Python Basics-exceptions, objects, and iterators