Requirement description: Verification form 1. When the area is mainland China, the mobile phone number is required but the contact number is not required; otherwise, the opposite is true. 2. Each email address should conform to the correct email format; when the warehouse type is a virtual warehouse, the email address is required, and in […]
Tag: condition
Pointer functions, called function access to heap space, function pointers, function pointer arrays, conditional compilation
Pointer function Concept The essence is a function, and the return value of the function is a pointer. It can be understood by analogy with an array of pointers. Pointer array: It is essentially an array, and the elements in the array are pointers. Pointer array format: *array name [number of elements]; For example: (auto) […]
MySQL’s optimization tool: Pushing down index conditions improves performance by 273% under tens of millions of data
MySQL’s optimization tool: the index conditions are pushed down, and the performance of tens of millions of data is improved by 273% Foreword In the previous stage, we talked about the selection of field types in MySQL and lamented the performance differences of different types under tens of millions of data. Time type: How to […]
Input, output and conditional judgment in C language
Table of Contents Data types, operators and expressions 1.Data type Basic data types include Ranges 2. Constants and variables constant variable Define variables Classification of variables Why use variables 3.Input and output Format output function printf() Output type when printing Format input function scanf() 4. Arithmetic operators and arithmetic expressions Two unary operators and five […]
JavaScript | 1000 judgment conditions require writing 1000 if? This article teaches you how to implement branch optimization
I recently saw this piece of code while surfing the Internet: function getUserDescribe(name) { if (name === “Xiao Liu”) { console.log(“Brother Liu”); } else if (name === “小红”) { console.log(“Sister Xiaohong”); } else if (name === “陈龙”) { console.log(“Master”); } else if (name === “李龙”) { console.log(“Master”); } else if (name === “Dapeng”) { console.log(“evil”); […]
Please explain conditional rendering in React.
Gathering sand into a tower, making a little progress every day ? Column introduction Front-end Getting Started Tour: Exploring the Wonderful World of Web Development Welcome to the Front-End Getting Started Tour! If you are interested, you can subscribe to this column! This column is tailor-made for those who are interested in web development and […]
JUnit5 conditional testing, nested testing, repeated testing
Conditional test JUnit5 supports conditional annotations to determine whether to execute a test based on a Boolean value. Custom conditions The @EnabledIf and @DisabledIf annotations are used to set custom conditions, example: @Test @EnabledIf(“customCondition”) void enabled() { // … } @Test @DisabledIf(“customCondition”) void disabled() { // … } boolean customCondition() { return true; } The […]
PHP preg_replace() Regularly replaces all strings that meet the conditions
PHP preg_replace() regular replacement is different from Javascript regular replacement. PHP preg_replace() defaults to replacing all elements whose symbols match the conditions. The data that we need to process with programs is not always designed in advance with database thinking, or it cannot be stored using the structure of a database. For example, template engine […]
JUnit5 conditional testing, nested testing, repeated testing
Conditional test JUnit5 supports conditional annotations to determine whether to execute a test based on a Boolean value. Custom conditions The @EnabledIf and @DisabledIf annotations are used to set custom conditions, example: @Test @EnabledIf(“customCondition”) void enabled() { // … } @Test @DisabledIf(“customCondition”) void disabled() { // … } boolean customCondition() { return true; } The […]
RHCE—Conditional judgment of process control
Article Directory Table of Contents Article directory Preface 1.if statement syntax double branch structure multi-branch structure case analysis Summarize Foreword In the command connection symbols & amp; & amp; and || have their own judgment conditions. This is the condition judgment learned in the shell basics. In script writing, the shell script has its own […]