• Advanced usage of shell programming variables


    catalogue Variable replacement Variable test string manipulation String length Substring character index Substring length Extract substring Small trial ox knife Command replacement Typed variable Expr of mathematical operation BC of mathematical operation Variable replacement grammar explain ${variable name # matching rule} Slave variablestartMatch the rules to meet theminimumData deletion for ${variable name ## matching rule} […]

  • The concept and characteristics of MySQL custom variable


    MySQL customization is a temporary container for storing values. As long as the connection with the server is active, the values in the container can be saved and used. You can set custom variables through simple set or select statements, as follows: SET @one := 1; SET @min_actor := (SELECT MIN(actor_id) FROM sakila.actor); SET @last_week […]

  • Notes on golang (2): types, variables and constants


    Basic types 1. List of basic types Copy codeThe code is as follows: type         length      explainbool          one       True / false, the default is false, and non-zero values cannot be regarded as true (no number is used to represent true / false)byte          one       Uint8 aliasrune          four       Int32 alias. […]

  • Detailed explanation of variable variable in pytorch


    1、 Understanding variables As the name suggests, variable means variable. In essence, it is a variable that can be changed. Different from int variable, it is a variable that can be changed. This is just in line with the properties of back propagation and parameter update. Specifically, the variable in pytorch is a geographical location […]

  • Explain constants and variables in golang programming


    Go language constant Constants are fixed values that the program may not be able to change during its execution. These fixed values are also called literals. A constant can be any basic data type like an integer constant, a floating-point constant, a character constant, or a string literal. There are also enumeration constants. Constants are […]

  • Three ways to declare golang variables


    There are three ways to declare variables in golang  One is to use VaR keyword to declare package level or function level variables;  The second is to use the short variable declaration method, which can only declare function level variables and need to specify the variable value;  Third, the const keyword is used to declare […]

  • Python variables, data types, data type conversion related function usage examples


    In this paper, examples about Python variables, data types, data type conversion function usage. The details are as follows: The use of Python variables does not require type declaration (type name, variable name). The value assigned to a variable name is the type. Variable assignment and use= Note: Although Python does not have a type […]

  • 15 important variables you must know about MySQL performance tuning (summary)


    preface: MySQL should be the most popular web back-end database. Although NoSQL has been mentioned more and more recently, I believe most architects will still choose MySQL as data storage. In this paper, the author summarizes and combs 15 important variables of MySQL performance tuning, and hopes to point out the deficiencies that need to […]

  • Perfect solution of topic switching based on CSS variable (recommended)


      When receiving this demand, there are still a lot of schemes from Baidu to the industry about topic switching, such as CSS link replacement, classname change, etc less.modifyVars But every solution sounds tired and expensive. Is there a low code intrusion, brainless and easy to maintain solution? Of course, there are. To be exact, […]

  • An example of gradient calculation for variables of non leaf nodes in Python


    In Python, gradient calculation is generally only performed on leaf nodes, that is, nodes D and E in the figure below, while for non leaf nodes, that is, nodes C and E, B node does not explicitly keep the gradient in the intermediate calculation process (because generally only leaf nodes need to be updated), which […]

  • Detailed analysis ASP.NET The C # variable of razor


    variable Variables are used to store data. The name of a variable must start with an alphabetic character and cannot contain spaces or reserved characters. A variable can be of a specified type, representing the type of data it stores. The string variable stores the string value (“welcome to” RUNOOB.COM “), integer variable stores numeric […]

  • PHP to see a variable of memory instance code


    example: PHP version is 7.2 <?php echo memory_get_usage() , ‘<br>’; $start = memory_get_usage(); $a = Array(); for ($i=0; $i<1000; $i++) { $a[$i] = $i + $i; } $mid = memory_get_usage(); echo memory_get_usage() , ‘<br>’; for ($i=1000; $i<2000; $i++) { $a[$i] = $i + $i; } $end = memory_get_usage(); echo memory_get_usage() , ‘<br>’; echo ‘argv:’, ($mid […]