python 2 7 tutorial

created.rewrite: A class can implement methods to override these methods and tree shapes defined in its superclass. If the new method calls the overridden version of the method, you can call the unbound version directly from the superclass or use the Super function.sequences and mappings: creating your own sequences or mappings requires methods that implement all the sequence and mapping rules, including __getitem__ and __setitem__, which are special methods. The subclass list and dict can save

first parameter, which is generally called self.class: A class represents a collection of objects, and each object has a class. The primary task of a class is to define the method that it uses for its instances.Polymorphism : polymorphism is an attribute that implements the same treatment of objects of different types and classes. You do not need to know which class the object belongs to to invoke the method.Encapsulation: objects can hide their internal state.Inheritance: A class can make a su

Concise Python tutorial --- 7. Functions A function is a reusable statement block. Many languages allow defining functions to specify a name for a statement block, and reuse the statement block countless times in other places of the program. In python, the def keyword is used to define functions. The def keyword is fo

Python object (or even some Python code form) and convert it into a string representation; this process is called pickling. The string indicates that the re-constructed object is called unpickling. Between pickling and unpickling, the object string indicates that it may have been stored in a file or data, or sent to some remote machines through the network. If you have an object X, and a file object F has

11. Object-Oriented Programming(1) IntroductionSlightly(2) SelfSuppose you have a class called MyClass and an instance of this class MyObject .When you call the method MyObject.method(arg1, arg2) of this object,This will be automatically converted MyClass.method(MyObject, arg1, arg2) by Python-that's how it self works .(3) classSlightly(4) Methods of the objectSlightly(5) __init__ methodSlightly(6) Var

. PopitemThe Popitem method is similar to List.pop, which pops up the last element of the list. But the difference is that popitem pops up random entries because the dictionary does not have "last element" or other concepts about the order. This method works well if you want to remove and process items one after the other, because you don't have to get the list of keys first.The dictionary does not have a method equivalent to append, because the dictionary is unordered, and a method similar to a

( ) This method returns a tuple of column names. Immediately after a query, it's the first member of each tuple in cursor.description. New in version 2.6. The following examples illustratein [+]: cx.row_factory = sqlite3. Rowin [+]: c = cx.cursor ()in [+]: C.execute (' select * from Catalog ')OUT[32]: In [all]: R = C.fetchone ()in [+]: type (R)OUT[34]: in [+]: ROUT[35]: In [approx]: print R(0, ten, U ' \u9c7c ', U ' Yu ')In [PNS]:

Here we will share how to install the Python program on the 64-bit Windows 7 system platform:Step 1: log on and download the programLog on to the Python official website https://www.python.org/We can see that there are two versions. Here I select Python 2.7.9Step 2: install

can throw an exception using the Raise statement. It accepts an exception class or an exception instance as a parameter, and can provide two parameters (exception and error information).　　Custom Exception classes: You can create your own exception classes by inheriting the methods of the exception class.　　catch Exception: use the except clause of the TRY statement to catch the exception. Exceptions can be placed in tuples to implement multiple exception sets. If the except is given two paramete

example width = input('Enter number here:')price_width = 10item_width = width - price_widthheader_format = '%-*s%*s'content_format = '%-*s%*.2f'print '='*widthprint header_format % (item_width,'Item',price_width,'Price')print '-'*widthprint content_format % (item_width,'Apples',price_width,0.4)print content_format % (item_width,'Pears',price_width,0.5)print content_format % (item_width,'Banana',price_width,8)print content_format % (item_width,'Tomato',price_width,6)print '='*width Outp