Variable type

Variable detection

Type detection

Debug print variables

type conversion

Assignment

destroy

Dynamic variable name

Three points to note about arithmetic operators

comparison operator

increment decrement operator

Logical Operators

increment decrement operator

String operators

assignment operator

switch case control structure

do while

for loop

break和continue

Bridge crossing problem

multiplication table

One hundred dollars buys one hundred chickens

Function concept

function definition format

Function execution and return process

Function parameter passing method

Optional parameters

function scope

Dynamically calling functions

timestamp function

Timestamp formatting

Date parsing function

String definition method

Escape, variable parsing, and speed comparison

Common string functions

file management system

Array definition method

array type

Array key rules

Operate array unit

Traverse array

Array cursor operations

Common functions for arrays

lamb breeding

superglobal variables

constant

File contains

Domain names and DNS

Configure virtual host

hexadecimal concept

Bit operations

Floating point numbers are not precise enough

Short-circuiting properties of logical operators

recursive concept

Recursive tricks

Recursion exercises

staticstatic variable