#http://kb.cnblogs.com/page/87128/(not finished) 2.7. Generator (Generator)The generator is an object returned by calling a generator function (generator functions), and is used more iteratively for collection objects.
__ITER__: is just an iterative marker.
Gi_c
generation mechanism (auto-increase field or sequence) is provided by commonly used databases such as Oracle, DB2, SQL Server, MYSQL, and so on. We can use Generator-class=native's primary key generation method on the primary key generation mechanism provided by the database. It is worth noting, however, that some databases provide a primary key generation mechanism that is not necessarily the most efficient, and that large amounts of concurrent inse
Introduction to Python iterator and generator, python Generator
Iterator
The iterator is an object that implements the iterator protocol. In Python, The iterator Protocol means that objects with the next method will move forward to the next result. At the end of a series of results, the StopIteration is triggered.
In the for loop, Python will automatically call the factory function iter () to obtain the it
Python function recursion and generator, python recursive Generator
1. What is recursion?
If a function contains a call to itself, the function is recursive. Recursion is an algorithm widely used in programming languages. It usually converts a large and complex problem into a small problem similar to the original problem to solve it, the recursive strategy can describe the repeated computing required for th
This example describes the Python builder generator usage. Share to everyone for your reference. Specifically as follows:
With yield, you can have a function generate a sequence of results, not just a value
For example:
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def countdown (n): print "Counting Down" while N>0:yield n #生成一个n值 n-=1 >>> C = Countdown (5) >>> C.N EXT () Counting down 5 >>> c.next () 4 >>> c.next () 3
Next () calls th
List Builder/list resolution lists comprehension
Simple and flexible to create lists, usually with lambda (), map (), filter ()
Create a list directly from a list of generated expressions. However, if you receive content restrictions, the list size is certainly limited. And, creating a list of 1 million elements, not only takes up a lot of storage space, but if we just need to access a few elements, then the other is white space. The list genera
Python iterator and generator instance details, python Generator
This article describes the python iterator and generator with examples, as shown below:
1. iterator Overview:An iterator is a way to access collection elements. The iterator object is accessed from the first element of the set until all elements are accessed. The iterator can only move forward witho
Prerequisites: If the function contains yield is the generator, the execution process encountered yield to jump out.Example:Def gen ():For I in range (10):x = Yield IPrint (x)G=ge ()Print (G.send (None)))Print (G.send (2))First say expression x = yield IIf this expression is only x = i, I believe everyone can understand. The value of I is assigned to X, and now the right side of the equals sign is a yield I, so I have to execute yield I first and then
New feature 3 of ES6: Generator (Generator) function details, es6 function details
This example describes the new feature 3 of ES6: Generator (Generator) function. We will share this with you for your reference. The details are as follows:
1. Introduction
① Understanding: it can be understood as a function's internal s
Write the code generator by yourself (1). Write the Code Generator
I thought of a code generator of my own for a long time. It was simple and enough for my own use, so I had no time. I was idle recently, so I made up my mind to write a small software to complete these tasks for me. I wanted to use WPF for development. However, WPF only learned basic things, and I
Use the generator to rewrite the function method that directly returns the list. The generator returns the list.
This article is a learning note in the article "objective Python", recording the sample code and ideas.
If a function produces a series of results, the simplest way is to put these results in a list and return them.
For example, we want to locate the position of the first letter of each word in t
Format comparison:List imprehensions Format: [Statement for ...]Generator format: (Statement for.. In.. )The difference: The list stores the specific content, each element occupies space, when the need to store n data, occupy a large spaceThe generator store is an expression that calculates the next element by calculation and therefore occupies less space.One, 2 kinds of input methods#!/usr/bin/python#Gener
Generator:(in Python, this side loop computes the mechanism, called the generator: Generator)ways to create generator:1. Turn the list generation [] into () and create a generatorExample:The next return value can be obtained by next () generatortraversing words can be used directly:For I in G:print (i)2. Change print (
Python3 iterator and generator, python3 Generator
Pythom3 iterator and GeneratorIterator'''The iterator is one of the most powerful functions of python and a way to access collection elements.The iterator is a location object that can remember to traverseThe iterator object is accessed from the first element of the set until all elements are accessed. The iterator can only move forward without moving back.T
Python generator, iteratable object, iterator difference and connection, python Generator
What is the relationship between generators, iteratable objects, and iterators?
Use a picture to summarize:
1. Generator
Definition Generator
Method 1:
// Unlike the list generator gen
First, generator definitionBy generating an expression from a list, we can create a list directly. However, with memory limitations, the list capacity is certainly limited. So, if the list element can be calculated according to an algorithm, can we continue to calculate the subsequent elements in the process of the loop? This eliminates the need to create a complete list, which saves a lot of space. In Python, this side loop computes the mechanism, ca
Python iterator, generator and decorator, and python generator Decoration
1. Principles and usage of the iterator:1> principle:An iterator is a way to access a set element. The iterator object is accessed from the first element of the set until all elements are accessed. The iterator can only move forward and not backward, but that's nothing. People seldom step back on the iteration process. In addition, th
Self-compiled DAL three-tier code generator and dal three-tier Code Generator
(1) Create your own solution directory structure as follows:
(2) Compile the Code:
(To use a database, we recommend that you create any database)
The code for creating the configuration file App. config is as follows:
The MainWindow. xaml code is as follows: (change the code in the Grid in MainWindow. xaml)
The MainWindow. xa
Python list derivation and generator expression usage example, python Generator
This article describes the Python list derivation and generator expression usage. We will share this with you for your reference. The details are as follows:
Like the list,List DerivationIt is also represented by square brackets [] and uses a abbreviated for loop. The first part is an
GeneratorGenerator function: The function body contains the yield keyword, the result of which the function executes is the generator, which is essentially an iterator.deffoo ():Print('First ------>') yield1Print('Second----->') yield2Print('Third----->') yield3Print('fouth----->') G=foo () fromCollectionsImportIteratorPrint(Isinstance (g,iterator))Print(g)Yield Features:1. Similar to return, can return a value, but the difference is that the
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