LUA学习笔记
注释
单行注释 --
多行注释 --[[
--]]
Lua数据类型
nil
boolean true/false
number 浮点
string
function C或Lua函数
userdata C数据结构
thread
table 关联数组
tab1 = { key1 = "val1", key2 = "val2", "val3" }
for k, v in pairs(tab1) do
print(k .. " - " .. v)
end
tab1.key1 = nil
for k, v in pairs(tab1) do
print(k .. " - " .. v)
end
字符串
'Lua'
"Lua"
[[Lua]]
变量
三种类型：全局变量，局部变量，表中的域
a = 5 全局变量
local b =5 局部变量
运算
运算符
算数: + - * / % ^
关系: == ~= > < >= <=
逻辑: and or not
字符串: # ..
> print("2" + 6)
8.0
> print("2" + "6")
8.0
> print("2 + 6")
2 + 6
> print("-2e2" * "6")
-1200.0
> print("a" .. 'b')
ab
> print(157 .. 428)
157428
print(#"www.runoob.com")
14
a, b = 10, 2*x <--> a=10; b=2*x
> site = {}
> site["key"] = "www.runoob.com"
> print(site["key"])
www.runoob.com
> print(site.key)
www.runoob.com
函数
普通函数
function factorial1(n)
if n == 0 then
return 1
else
return n * factorial1(n - 1)
end
end
print(factorial1(5))
factorial2 = factorial1
print(factorial2(5))
匿名函数
function testFun(tab,fun)
for k ,v in pairs(tab) do
print(fun(k,v));
end
end
tab={key1="val1",key2="val2"};
testFun(tab,
function(key,val)--匿名函数
return key.."="..val;
end
);
可变参数
function average(...)
result = 0
local arg={...} --> arg 为一个表，局部变量
for i,v in ipairs(arg) do
result = result + v
end
print("总共传入 " .. #arg .. " 个数")
return result/#arg
end
print("平均值为",average(10,5,3,4,5,6))
function average(...)
result = 0
local arg={...}
for i,v in ipairs(arg) do
result = result + v
end
print("总共传入 " .. select("#",...) .. " 个数")
return result/select("#",...)
end
print("平均值为",average(10,5,3,4,5,6))
多返回值
function maximum (a)
local mi = 1 -- 最大值索引
local m = a[mi] -- 最大值
for i,val in ipairs(a) do
if val > m then
mi = i
m = val
end
end
return m, mi
end
print(maximum({8,10,23,12,5}))
循环
a=10
while( a < 20 )
do
print("a 的值为:", a)
a = a+1
end
for i=10,1,-1 do
print(i)
end
for i=1, (function (x)
return x*2
end)(5) do print(i)
end
days = {"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"}
for i,v in ipairs(days) do print(v) end
a = 10
repeat
print("a的值为:", a)
a = a + 1
until( a > 15 )
分支
if(0)
then
print("0 为 true")
end
字符串
string.upper(argument)
string.lower(argument)
string.gsub(mainString,findString,replaceString,num)
string.find (str, substr, [init, [end]])
string.reverse(arg)
string.format(...)
string.char(arg)
string.byte(arg[,int])
string.len(arg)
string.rep(string, n)
string.gmatch(str, pattern)
string.gmatch("Hello Lua user", "%a+")
string.match(str, pattern, init)
string.match("I have 2 questions for you.", "%d+ %a+")
数组
array = {"Lua", "Tutorial"}
for i= 0, #array do
print(array[i])
end
-- 多维数组
array = {}
for i=1,3 do
array[i] = {}
for j=1,3 do
array[i][j] = i*j
end
end
迭代器
for k, v in pairs(t) do
print(k, v)
end
array = {"Google", "Runoob"}
function elementIterator (collection)
local index = 0
local count = #collection
-- 闭包函数
return function ()
index = index + 1
if index <= count
then
-- 返回迭代器的当前元素
return collection[index]
end
end
end
table
table.concat (table [, sep [, start [, end]]])
table.insert (table, [pos,] value)
table.maxn (table)
table.remove (table [, pos])
table.sort (table [, comp])
模块
require("模块名")
require "模块名"
local path = "/usr/local/lua/lib/libluasocket.so"
local f = loadlib(path, "luaopen_socket")
