Lua Foundation

Lua The declared variables are global variables by default , Declare local variables plus local Prefix , such as local a Express a Is a local variable

Variables that have not been declared are nil, Similar to other languages null

Support multiple assignments ：a,b=1,2

Lua There is number type ： Double precision type ,c in int,float,double All belong to lua Of number type

Lua And support 16 Mechanism representation , It also supports scientific counting , Support the operation of moving left and right

character string

Lua String type （string）： Use single or double quotation marks to represent the string , Escape character support

The string connection operation is not a plus sign, but two points , Like strings a, character string b, take a and b The connection is a..b

Number Convert to character type ：c=tostring(10)

Convert character type to number：n=tonumber（“10”）, If the conversion fails n Namely nil

Get string length ： Precede the string with #, such as #c You can get c Length of string

Lua function

You can also write like this

Table：

Table Numeric subscript

Extract the elements inside with subscripts , however lua Subscript from 1 Start

Table Everything in it can be stored

Insert elements ：table.insert(a,”d”) stay table a Insert... At the end of d

You can also specify the insertion position ：table.insert(a,2,”d”) stay table a Insert in the second position of d

Remove elements ：table.insert(a,,2) Remove the second element , Passing will also return the removed element

Table String subscript ：

Similar to hash table

Print elements

Additive elements

Global table _G

All global variables are in the global table

stay lua There's only false and nil On behalf of false , Everything else stands for truth , such as 0 It's true, too

Branch judgment statement

use then and end Represents a block of code

Loop statement

For loop ：

initial value 1, End value 10, You can also add another parameter ： step

  Here the step size is 2

Here in the face of i It cannot be changed

When i be equal to 5 To exit the loop

While loop

do end It's a block of code

Out-of-service n-=1