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
The project is a common code generator for the Javaweb project, generates the corresponding Jsp,js,java file according to the database table and custom code template, generates the Javaweb Project development tool under the specified path;Project Open Source Address: https://gitee.com/okrs.cn/CodeGeneratorCode generator:The project is a code generator based on the Apache Velocity Java template engineBase_bu
MyBatis Generator (MBG) is a MyBatis code generator that helps us generate corresponding entity classes, XML mapper files, interfaces, and help classes based on the design of tables in the database (that is, we can use this class for simple crud operations). This avoids the need to manually create the corresponding classes and XML files for each table of data, which saves us a lot of time to develop functio
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
Additional example of listening file enddeftail (): F= Open ('file','R', encoding='Utf-8') F.seek (0,2) whileTrue:line=F.readline ()ifLine :yield LineImportTime Time.sleep (0.1) G=tail () forIinchg:Print(I.strip ())Send methodSend method:deffunc ():Print('*'*10) A=yield5Print(a)yield10g=func ()Print(g.__next__())Print(G.send ('Wenwen'))#print (g.__next__ ())From which yield begins to execute, send passes a value to the yieldSend cannot be used in the first touch generatorThe number of yield
Python3 generator and python3 Generator
1 ''' 2 list generation type 3''' 4 5 # a1 = [x for x in range (10)] 6 # a2 = [x * 2 for x in range (10)] 7 # print (a1) 8 # print (a2) 9 #10 # def fun1 (x ): 11 # return x ** 3 12 # a3 = [fun1 (x) for x in range (10)] 13 # print (a3) 14 #15 # list generation type 16 # Value Method 17 # B = ['asd ', 8, 9, 10] 18 # w, x, y, z = B 19 # print (w, x, y, z) 20 # print (B)
* Using the generator to process CSV files Input:.. /data/t_video.csv"9", "Other", "ULTIMATE PHOTO Guide", NULL, "Http://118.190.209.209/media/mp4/1.mp4", "http://118.190.209.209/media/png/ 1.png "," ULTIMATE PHOTO Guide "" 10 "," other "," the VERGE ", NULL," Http://118.190.209.209/media/mp4/2.mp4 ","/HTTP/ 118.190.209.209/media/png/2.the_verge.png "," The Verge "" 11 "," Other "," Microsoft Power BI ", NULL," http://118.190.209.209 /media/mp4/3.mp4
PHP Generator Simple instance, PHP generator
Generally when you iterate over a set of data, you need to create a data, assuming that the array is large, it consumes a lot of performance, or even causes memory shortage.Copy the Code code as follows:Fatal error:allowed memory size of 134217728 bytes exhausted (tried to allocate + bytes) in E:\php\test\index.php on L INE 5Range (1, 100000000);
PHP5.5 implemen
Four arithmetic question generator (C ++) and four arithmetic question Generator
Question: Four arithmetic question generator.
Idea: Use the rand () % 100 function to generate a random positive integer of less than 100. Likewise, use the random function rand () % 4 to generate random 0, 1, 2 and 3 are random integers corresponding to the four conditions of additi
Simple PHP generator instance, php Generator
Generally, when you iterate a set of data, you need to create a data. If the array is large, it will consume a lot of performance, and even cause insufficient memory.Copy codeThe Code is as follows:// Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 32 bytes) in E: \ php \ test \ index. php on line 5Range (1, 100000000 );
PHP5.5
PHP hexadecimal random color generator function example, hexadecimal Generator
This example describes the PHP hexadecimal color random generator function. We will share this with you for your reference. The details are as follows:
Running result: #8ABED4
PS: Here are some related color tools for your reference:
RGB color encoding generator:Http://tools.jb51
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