PHP language introduction

PHP software introduction

PHP variables, variable naming rules

Variable type Boolean type, integer type, floating point type, string, null value

Type conversion boolval intval floatval strval

Type judgment function is_bool is_int is_float is_string is_null

Ouyang Ke's Vernacular Chapter (can be skipped)

Arithmetic operators, string operators, assignment operators

Increment and decrement operators, logical operators, comparison operators

Conditional operators, operator precedence

PHP conditional control statement if()

PHP conditional control statement switch() exit;

PHP loop control statement while()

PHP loop control statement for() break; continue();

Single quotes, double quotes, string escape, trim(), ltrim(), rtime()

String length, comparing two strings

search string

Replace strings and format numbers

Create array, array type, output array

One-dimensional array, multi-dimensional array, array traversal foreach()

Array to string, string to array, count the number of array elements

Query array keys, query data elements, add and delete array elements

Detect arrays, merge arrays, and sort arrays

superglobal variable

Custom function

Introduction to classes and objects, creation and instantiation of classes, members of classes

Class value transfer, construction method, class inheritance, class polymorphism

class magic methods

Trait

Namespaces