while和repeat

indx = 1
while indx < 10 do
    indx = indx + 1
end

repeat
    indx = indx + 1
until indx > 10

for語句:Lua中的for語句迴圈次數在第一次就確定了，後面不改變

for indx = 1,10 do
    print(indx)
end

for
 
 indx = 1,10,-1 do
    print(indx)
end

函式

function SetName(myString)

end

function SetName(...)
    if arg.n >0 then
        for indx = 1,arg.n do
        local myString = string.format("%s%d","Argument ",indx,":")
        end
    else
        print(myString,arg[indx]);
    end
end

function Multiply
 
(val1,val2,...)
    local myString
    if arg.n == 0 then
        myString = string.format("%d%s%d%s%d",val1,"*",val2,"=",val1*val2)
    else
        local val3 = val1*val2*arg[1]
        myString = tring.format("%d%s%d%s%d%s%d",val1,"*",val2,"*",arg[1],"=",val3)
    end
    print(myString)
end

返回值return

function TimesTwo(myValue)
    myValue = myValue*2
    return myValue
end

a = 24 + TimesTwo(12)
print(a)

function ThreeDice()
    d1 = math.random(1,6)
    d2 = math.random(1,6)
    d3 = math.random(1,6)
    myTotal = d1 + d2 +d3
    return d1,d2,d3,myTotal
end

a,b,c,d = ThreeDice()

assert函式

a = "hello world"
b = "print(a)"
assert(loadstring(b))()

輸出：
helloworld

math.random()

myDie = math.random(1,6)
--設定隨機數發生種子
\math.randomseed(os.date(%d%H%M%S))

math.min()：判斷table裡的資料最小值，與loadstring配合

myTable = {7,1,13,6,89,4,56,2,54,6}
function GetMin(theTable)
    myString = "myValue = math.min("
    for index,value in ipairs(theTable) do
        myString = string.format("%s%d%s", myString, value, ",")
    end
    --remove final comma
    myString = string.sub (myString, 1, string.len(myString) - 1)
    myString = string.format("%s%s", myString, ")")
    loadstring(myString)() --run the chunk
    print(myString) -- see the string
    print(myValue) --see the result
    return myValue
end

字元和格式：

myString = "The price is $17.50."
filter = "$%d%d.%d%d"
print(string.sub(myString,string.find(myString,filter)))
--$17.50

string.gsub(sourceString,pattern,replacementString)
--返回一個字串，sourceString字元中，滿足pattern格式的字元都會被替換成replacementString引數的值
eg:

myString = "My name is John Smith. My phone is 555-3257"
newString = string.gsub(myString,"%d","*")
--My name is John Smith. My phone is ***-***

a = "(309) 555-1234"
print(string.gsub(a,"%(%d%d%d%)","(781)"))
--(781) 555-1234

a = "happy, hello, home, hot, hudson"
print(string.gsub(a,"h%a+","An H world!",2))
--An H world!, An H world!, home, hot, hudson
--查詢以h開頭的字元，%a+表示任意長度的字母，並在遇到空格和標點符號時為止，最後的引數2表示只替換最先遇到的兩個

string.gfind(string,pattern)注意是遍歷字串，只要滿足指定格式就返回該子串
a = "This is my rather long string."
for v in string.gfind(a,"%a+") do
    print(v)
end
--This
  is
  my
  rather
  long
  string

table資料結構
table.getn()
table.sort()

--sort有可選的引數, 此引數是一個外部函式, 可以用來自定義sort函式的排序標準.此函式應滿足以下條件: 
--接受兩個引數(依次為a, b), 並返回一個布林型的值, 當a應該排在b前面時, 返回true, 反之返回false.
--下面是一個逆序排序，當direction=1時逆序
function Sort(theTable, direction)
    if direction ~= 1 then
        table.sort(theTable)
    else
        function Reverse(a, b)
            if a < b then
                return false
            else
                return true
            end
        end
        table.sort(theTable, Reverse)
    end
end

table.insert(myTable,position,value)預設是末尾
table.remove(myTable,position) 預設是末尾，且返回去除值

多維table

widget = {}
widget.name = {}
widget.cost = {}
widget.name[1] = "Can opener"
widget.cost[1] = "$12.75"
widget.name[2] = "Scissors"
widget.cost[2] = "$8.99"

pairs()：遍歷table中的每一個元素

myName = {"Fred","Ethel","lucy","Ricky"}
for index,value in pairs(myName) do
    print(index,value)
end

for index = 1,table.getn(myNames) do
    print(index,myName[index])
end

I/O基礎

利用io可以生成可執行的lua檔案，可以用於遊戲資料或者遊戲進度的儲存

myFile = io.open("xxx.lua","w")--檔案不存在則新建 w代表寫入
if myFile ~= nil then
    myFile:write("--Test lua file")
    myFile:write(string.char(10))--換行
    myFile:write(string.format("%s%s","--File created on:",os.date()))
    myFile::write("print(\"helloworld!\")")
    io.close(myFile)
end