PHP development basics - Strings

• Chapter1 Preparation
• 1-1 Summary of string output methods
• Chapter2 Common string functions (Part 1)
• 2-1 String filtering and filling
• 2-2 Case conversion and usage scenario analysis
• 2-3 Parsing and restoring HTML tags and special characters
• Chapter3 Common string functions (Part 2)
• 3-1 Commonly used string search functions
• 3-2 Classic string replacement operation skills
• 3-3 Introduction to common operation functions of URL and JSON