PHP language classic introductory tutorial

• Chapter1 Introduction to PHP
• 1-1 PHP language introduction
• 1-2 PHP software introduction
• Chapter2 PHP variables
• 2-1 PHP variables, variable naming rules
• 2-2 Variable type Boolean type, integer type, floating point type, string, null value
• 2-3 Type conversion boolval intval floatval strval
• 2-4 Type judgment function is_bool is_int is_float is_string is_null
• Chapter3 PHP operators
• 3-1 Ouyang Ke's Vernacular Chapter (can be skipped)
• 3-2 Arithmetic operators, string operators, assignment operators
• 3-3 Increment and decrement operators, logical operators, comparison operators
• 3-4 Conditional operators, operator precedence
• Chapter4 PHP process control
• 4-1 PHP conditional control statement if()
• 4-2 PHP conditional control statement switch() exit;
• 4-3 PHP loop control statement while()
• 4-4 PHP loop control statement for() break; continue();
• Chapter5 PHP string
• 5-1 Single quotes, double quotes, string escape, trim(), ltrim(), rtime()
• 5-2 String length, comparing two strings
• 5-3 search string
• 5-4 Replace strings and format numbers
• Chapter6 PHP array
• 6-1 Create array, array type, output array
• 6-2 One-dimensional array, multi-dimensional array, array traversal foreach()
• 6-3 Array to string, string to array, count the number of array elements
• 6-4 Query array keys, query data elements, add and delete array elements
• 6-5 Detect arrays, merge arrays, and sort arrays
• 6-6 superglobal variable
• Chapter7 PHP object
• 7-1 Custom function
• 7-2 Introduction to classes and objects, creation and instantiation of classes, members of classes
• 7-3 Class value transfer, construction method, class inheritance, class polymorphism
• 7-4 class magic methods
• 7-5 Trait
• 7-6 Namespaces