[Lua]lua初识

简介: -- mac 上有很多文本编辑器,Himi找了很多,感觉TextMate是比较好用的,小巧且功能强大!而且免费,图标是个小菊花 - --- 注释语句 --[[  注释段落语句  ]]-- --引用其他lua文件,不需要加上(.

-- mac 上有很多文本编辑器,Himi找了很多,感觉TextMate是比较好用的,小巧且功能强大!而且免费,图标是个小菊花 - -
-- 注释语句
 
--[[ 
注释段落语句
   ]] --
 
--引用其他lua文件,不需要加上(.lua)后缀
--require "xx"
 
--变量不需要定义,可以直接赋值
count = 100  --成员变量
local count = 100  --局部变量
 
--方法定义
function hello ( ... )
     --打印
     print ( "Hello Lua!" ) ;
     print ( string .format ( ... ) )
end
 
-- 每一行代码不需要使用分隔符,当然也可以加上
-- 访问没有初始化的变量,lua默认返回nil
 
-- 调用函数形式
hello ( "你懂的" )
 
--打印变量的类型
isOK = false
print ( type ( isOK ) )
 
-- 基本变量类型
a = nil --Lua 中值为nil 相当于删除
b = 10
c = 10.4
d = false
--定义字符串,单引号,双引号都可以的
e = "i am"
d = 'himi'
 
--两个字符串的连接可以如下形式
stringA = "Hi"
stringB = "mi"
print ( stringA..stringB )
 
--另外Lua也支持转移字符,如下
print ( stringA.. "\n" ..stringB ) ;
 
--修改字符串的部分gsub,可以如下形式:(将stringA字符串中的Hi修改为WT)
stringA = string .gsub ( stringA , "Hi" , "WT" )
print ( stringA ) ;
 
--将字符换成数字tonumber(不转也会自动转)
--将数字换成字符tostring(不转也会自动转)
stringC = "100"
stringC = tonumber ( stringC )
stringC = stringC + 20
stringC = tostring ( stringC )
print ( stringC )
 
--取一个字符串的长度使用 #
print ( #stringC)
 
--创建 表
tableA = { }
m = "x"
tableA[m] = 100
m 2 = 'y'
tableA[m 2 ] = 200
print ( tableA[ "x" ].. "\n" ..tableA.y )
--另外表还可以如下形式(从1开始)
tableB = { "4" , "5" , "6" , "7" , "8" }
print ( tableB[ 1 ] )
 
--算术操作符
c 1 = 10 + 2
c 2 = 10 -2
c 3 = 10 * 2
c 4 = 10 / 2
c 5 = 10 ^ 2
c 6 = 10 % 2
c 7 = -10 + 2
print ( c 1. . "_" ..c 2. . "_" ..c 3. . "_" ..c 4. . "_" ..c 5. . "_" ..c 6. . "_" ..c 7 )
 
--控制操作
--if then elseif then else end
abc = 10
if  abc = = 10 then
     print ( "v1" )
elseif abc = = 9 then
     print ( "v2" )
else
     print ( "v3" )
end
 
--for
--从4(第一个参数)涨到10(第二个参数),每次增长以2(第三个参数)为单位
for i = 4 , 10 , 2 do
     print ( "for1:" ..i + 1 )
end
--也可以不制定最后一个参数,默认1的增长速度
for i = 4 , 10 do
     print ( "for2:" ..i + 1 )
end
 
tableFor = { "himi1" , "himi2" , "himi3" , "himi4" , "himi5" }
for k , v in pairs ( tableFor ) do
     print ( "for3:key:" ..k.. "value:" ..v )
end
 
--while
w 1 = 20
while true do
     w 1 = w 1 + 1
     if w 1 = = 25 then
         break
     end
end
print ( "whlile:" ..w 1 )
 
--repeat
     aa = 20
     repeat aa = aa + 2
         print ( "repeat:" ..aa )
     until aa > 28
 
--关系操作符
--需要注意的是不等于符号 ~=  而不是!=
ax = 10
bx = 20
 
if ax > bx then
     print ( "GX1" )
elseif ax < bx then
     print ( "GX2" )
elseif ax > = bx then
     print ( "GX3" )
elseif ax < = bx then
     print ( "GX4" )
elseif ax = = bx then
     print ( "GX5" )
elseif ax~ = bx then
     print ( "GX6" )
else
     print ( "GX7" )
end


关于函数

--函数详解
 
--有一个返回值的函数
function funTestBackOne ( aCount )
     local aCount = aCount + 1
     return aCount
end
 
a = 20
print ( funTestBackOne ( a ) )
 
--有多个返回值的函数
function funTestBackMore ( )
     return 2 , 3
end
 
a , b = funTestBackMore ( )
print ( a.. " and " ..b )
 
--有变长参数的函数
function funTestUnKnow ( ... )
     print ( ... )
end
funTestUnKnow ( a , b , "Himi" )
 
--闭合函数(一个函数写在另外一个函数内)
function funTest 1 ( ... )
     local d = 12 ;
     d = d + ...
     function funTest 2 ( ... )
         print ( d )
     end
     funTest 2 ( )
end
 
funTest 1 ( 100 )

day1

--[[function fuc(n)

if n==0 then
return 1
else
return n*fuc(n-1)
end
end


print("input a number")
a = io.read("*number")
print(fuc(a))
--]]

--替换字符串
--[[
a = "one thing"
b = string.gsub(a,"one","two")
print(a)
print(b)
--]]

--转换数字
--[[
line = io.read()
n = tonumber(line)
if n==nil then
error(line.."is not a valid number")
else
print(n*2)
end
--]]

 

--拼接字符串
--[[
print("10"+1)

print("hell".."o")
--]]

--转换
--[[
line = io.read()
n = tonumber(line)
print(n)

print("我是一个字符串"..tostring(n))

print("10"=="10")
print(tostring(10)=="10")
--]]

--#计算长度
--[[
a = "hello"
print(#a)
print(#"good\0byte")
]]--


--table的使用
--[[
a = {}
k = "x"
a[k] = 10
a[20] = "great"
print(a[k])
print(a[20])
k = 20
print(a[k])
a["x"] =a["x"]+1
print(a["x"])

--使用同一个table
a = {}
a["x"] = 10
b = a --a和b使用了同一个table
print(b["x"])
b["x"] = 20
print(a["x"])
a = nil --b还在用table
b = nil --没人用table了

--自动增长
a = {}
--创建1000个新条目
for i = 1,1000 do a[i] = i*2 end
print(a[9])
a["x"] = 10
print(a["x"])
print(a["y"])
a.x = 20
print(a["x"])
print(a.x)

--循环存储值
a = {}
for i = 1,10
do a[i] = io.read() end

--输入打印数组的值
for i = 1,#a do
print(a[i])
end
--输出最后一个值
print(a[#a])
a[#a] = nil --删除最后一个值
a[#a + 1] = v --将v添加到列表的末尾
--]]

--[[
a = {}
a[1000] = 10
a[10000] = 11
print(table.maxn(a))


a = {}
i = 10;j = "10";k = "+10"
a[i] = "one value"
a[j] = "another value"
a[k] = "yet another value"
print(a[i])
print(a[j])
print(a[k])
print(a[tonumber(j)])
print(a[tonumber(k)])
--]]

--取小数点后面几位
--[[
x = math.pi
print(x%0.1)
print(x - x%0.01)


local tolerance = 10
function isturnback(angle)
angle = angle%360
return (math.abs(angle-180)<tolerance)
end
print(isturnback(-180))
--]]

--[[
a = 10
b = "10"
if tostring(a)~=b then print("不等")
else
print("相等")
end
--]]

--[[
a = {}
a.x = 1
a.y = 2
b = {}
b.x = 1
b.y = 2
c = a --a 等于 c table只有两个变量引用同一个的时候才是相等的
if a==b then print("a==b")
else
print("a~=b")
end
--]]

--[[

days = {"Sunday","Monday","Tuesday","Wednessday","Thursday","Friday","Saturday"}
print(days[1]) --这里注意不是从0开始

--a={x = 10,y = 20} <=>a = {};a.x = 10;a.y = 20


w = {x = 0,y = 0, label = "console"}
x = {math.sin(0),math.sin(1),math.sin(2)}
w[1] = "anther field"
x.f = w
print(w["x"])
print(w[1])
print(x.f[1])
w.x = nil
--]]


--[[
list = nil
for line in io.lines() do
list = {next = list,value = line}
end

local l = list
while l do
print(l.value)
l = l.next
end
--]]


--error("inva operation")

--相当于do while
--[[
repeat
line = io.read()
until line ~=""
print(line)


for i = 1,math.huge do --math.huge 无限大
print(1)
end
--]]

 

--[[
days = {"Sunday","Monday","Tuesday","Wednessday","Thursday","Friday","Saturday"}

revDays = {["Sunday"] = 1,["Monday"] = 2,["Tuesday"] = 3,["Wednessday"] = 4,["Thursday"] = 5,["Friday"] = 6,["Saturday"] = 7}
x = "Tuesday"
--print(revDays[x])

table.sort(revDays)
revDays1 = {}
for k,v in pairs(revDays) do --给v赋值“Sunday","Monday"... k赋值1,2...
print(k)
print(v)
end

--数组排序
a = {1,3,2}
table.sort(a)
for i,v in pairs(a) do print(v) end

--]]


--print("Monday是第"..revDays1["Monday"].."天")

--[[
for key,value in ipairs(revDays1) do
print(revDays1[key])
end
--]]

--[[
a = {}
a[1] = 10
a[2] = 20
a[3] = 30
for i,v in pairs(a) do print(v) end
--]]

 

 


day2

--函数
--数组求和

--[[
function sum(a)
local sum = 0
for i,v in pairs(a) do
sum = sum + v
end
return sum
end

a = {1,2,3,4,5,6}
num = sum(a)
print(num)


s,e = string.find("hello lua","lua")
print(s,e) --返回函数的开始结束字符,从1开始

--]]


--返回多个返回值
--[[
function maximum(a)
local mi = 1
local m = a[mi]
for i,val in pairs(a) do
if val> m then
mi = i;m = val
end
end
return m,mi
end
--]]

--[[
function maxmum(a)
local num = 1
local val = a[num]
for i,value in pairs(a) do
if value>val then
num = i
val = value
end
end
return val,num
end


print(maxmum({8,10,23,12,5}))
--]]

t = {}
s = "from=world, to=Lua"
for k, v in string.gmatch(s, "(%w+)=(%w+)") do
t[k]=v
end
for k, v in pairs(t) do
print(k,v)
end

 


print({if not package.loaded["111"] then print("nil") end}

 

 

day3

 

--面向对象

People = {} --定义一个p表

function clone(tab)
local t = {}
for key,value in pairs(tab) do
t[key] = value
end
return t
end


--[[
function People.sayhi()
print("Hello World")
end--]]

--[[People.sayhi = function()
print("Hello People ")
end--]]


function People.new(name)
local self = clone(People)
self.name = name
return self
end

People.sayhi = function(self)
print("Hello People "..self.name)
end


--[[q = clone(People)
q.sayhi()--]]


local k = People.new("丁小未")
k.sayhi(k)
k:sayhi(k)
--k.sayhi()

 

--继承

function copy(dist,tab)
for key,value in pairs(tab) do
dist[key] = value
end
end


Man = {}

Man.new = function(name)
local self = People.new(name)
copy(self,Man)
return self
end

Man.sayHello = function()
print("Man say hello")
end

Man.sayhi = function(self)
print("hi "..self.name)
end

local m= Man.new("人")
m.sayhi(m)
m:sayHello()
--m:sayhi(m)

 

 

 

lua不支持函数重载

 

--可变参数

function show(...)
local num = select('#',...)
if num>0 then
print("恩")
else
print("无")
end
end

show()

 

function clone(tab)
local t = {}
for key,value in pairs(tab) do
t[key] = value
end
return t
end


--[[
function People.sayhi()
print("Hello World")
end--]]

 


function People.new(name)
local self = clone(People)
self.name = name
return self
end

People.sayhi = function(self)
print("Hello People "..self.name)
end

 

local k = People.new("丁小未")
k.sayhi(k)

 

 

--原表

local tbA = {a = 1}
local tbB = {b = 2}
tbA.y = function(tb, k) --必须要有返回值
print("__index key:" .. k)
if k == 'a' then
return 10
end
return nil
end
--[[
local mt = {__index = tbA,
__newindex = function(t, k, v)
end
}

local mt = {__index = function(tb, k)   --这个元方法用于读取值
print("__index key:" .. k)
if k == 'a' then
return 10
end
return nil
end,
__newindex = function(tb, k, v)  --这个是用于设置值
print("__newindex key:" .. k)
end
}
]]
setmetatable(tbB, tbA)
tbB.a = 3
print(tbB.a)
--tbB.d = 3
--tbB.b = 5
--print(tbB.d)

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