generator google

What is a generator?A generator is a function that contains the special keyword yield. When called, the generator function returns a generator. You can use the send, throw, and close methods to allow the generator to interact with the outside world. The

Python learning diary: day13 ------ iterator and generator, pythonday13 ------I. Import 1. the dir function print (dir ([]) tells me that all the methods in this list contain double underscores. 2. The returned value after a list executes _ iter _ () is an iterator 3, the number of _ length_hint _ elements 4, and the value of _ setstate _ from the specified position is 5, []. _ iter _ () iterator ----> _ next _ you can use next to get values from the

()) # Print (i.__next__ ()) # Print (i.__next__ ()) # Print (i.__next__ ()) #StopIteration　　　　Iterator determines whether an iterator object iterabl is required to iterate over the object as an iterative object. __iter__ () is converted to an iterator to iterate over an iterator object that can iterate the iterator directly to the application: 1 provides a unified iterative Method 2 lazy computation that does not depend on the index, For example, to fetch each line of a fileIv.

, 8, 12]]This in turn writes the same as follows:transposed = []for i in Range (4): transposed_row = [] for row in matrix: transposed_row.append (Row[i]) Transposed.append (transposed_row) Print transposed# [[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]There is also a python built-in function zip (), also can be implemented as above functionZip (*matrix) # [(1, 5, 9), (2, 6, 10), (3, 7, 11), (4, 8, 12)]2.del statement (The DEL statement)>>> a = [-1, 1, 66.25, 333, 333, 1234.5]>>

exactly the same:>>> for N in Fab (5): ... Print N ... 1 1 2) 3 5　　Simply put, the function of yield is to turn a function into a generator, the function with yield is no longer a normal function, the Python interpreter treats it as a generator, and the Call to FAB (5) does not execute the FAB function, but instead returns a Iterab Le Object! When the For loop executes, each loop executes the code

) return Ncalc (8) The result is: 84.02.0n:2.0res:2.0n:4.0res:4.0n:8 Second, generator The generator is a function with a yield statement. A function or subroutine is returned only once, but a generator can pause execution and return an intermediate result, returning a value to the caller and pausing execution. When the next () method of the

The running process of next and send in the Python generator (detailed description) and pythongenerator For a normal generator, the first next call is equivalent to starting the generator. It starts to execute the first line of code of the generator function until the first execution of the yield statement (row 4th) is

eliminates the need to create a complete list, which saves a lot of space. In Python, this side loop computes the mechanism, called the Generator (Generator).To create a generator, there are a number of ways, the first method is simple, as long as a list-generated [] is changed to (), a generator is created: for inch

In fact, it should have been released early. I am probably the first batch of people to sort out Google's skills in China. Later, sniper wrote Google hack, which made it even lazy. Now I am helping my wife find a paper, and the keyword matching is so tired. These skills are after I sort them out. If you are interested, you can ask for them directly. Http: // www.feelids.com By swap The intra-site search address is: Http://www.google.com/custom? Do

Based on the revision and source code analysis of mybatis-generator-core 1.3.5, mybatisgeneratorcoreProject Description Mybatis-generator is used to generate code files such as entity classes based on database tables and fields. During the National Day, I analyzed the mybatis-generator-core source code and wrote quite detailed Chinese comments. Let's take a look.

first, the new test projectCreate a new MAVEN project MybatisDemo2, modify Pom.xml to introduce dependencies. Dependencies added on the previous sectionDependency> groupId>Org.mybatis.generatorgroupId> Artifactid>Mybatis-generator-coreArtifactid> version>1.3.2version>Dependency>Build Add PluginBuild> Plugins> plugin> groupId>Org.mybatis.generatorgroupId> Artifactid>Mybatis-