Lua：简单入门

i = 0while(i < 5)
doprint(i)
    i = i + 1end

x = 1if(x > 0)
thenprint(x)
end

x = 1repeatprint(x)
    x = x + 1until x == 5

            for i=1,5,1do--以步长为1从1递增到5print(i)
end

a = {{1,2}, {2, 4}, {3, 6}}
for i,v inipairs(a) doprint(i, v[1], v[2])
end

            function max(num1, num2)  --函数声明-函数名-参数列表if(num1 > num2) then
        result = num1;
    else
        result = num2
    endreturn result
endprint(max(1, 3))
print(max(5, 8))

            function
             max(num1, num2)  
    
            if(num1 > num2) then
        result = num1;
    else
        result = num2
    endreturn2, result
end

_, a = max(1, 3)
_, b = max(5, 6)
print(a)
print(b)

            function
             average(...)
    
            local args = {...}
    result = 0for k,v inipairs(args) do
        result = result + v
    end

    result = result / #args
    return result
endprint(average(1,4,5,10))

str_test = "Hello Lua"print(str_test)
pos = string.find(str_test, "Lua", 1) --#3为开始检索的偏移print(pos)

str_test = string.format("I am learn Lua for %d hous.", 2)
print(str_test)
print(string.len(str_test))

print(str_test .. " It.s amazing.")      --连接字符串print(string.byte("Test", 1))  --将字符串的字符转为asciiprint(string.char(99))         --将ascii转为字符

array = {{1, 2}, {2, 4}, {4, 8}}

for i=1,3dofor j = 1,2doprint(array[i][j])
    endend

fruits = {"apple", "banana", "orange"}

print(table.concat(fruits))       --将每个子项直接相连print(table.concat(fruits,", "))  --将子项之间通过", "相连print(table.concat(fruits, ", ", 1, 2))  --将前2项相连，舍弃第3项table.insert(fruits, "watermalon")  --在末尾插入print(fruits[4])

table.insert(fruits, 2, "pomelo")   --在第2个位置插入print(fruits[2])

table.remove(fruits, 2)  --移除第2个位置的项print(fruits[2])

table.sort(fruits)   --排序for k,v inipairs(fruits) doprint(v)
endtable.sort(fruits, function (fruit_1, fruit_2) returnstring.len(fruit_1) > string.len(fruit_2) end)    --自定义排序for k,v inipairs(fruits) doprint(v)
end

other = { member_1 = "A", member_2 = "B" }     --基础表元素
entity_1 = setmetatable({ member_0 = "Words" }, { __index = other })    --添加元表print(entity_1.member_0)    --打印基础元素print(entity_1.member_1)    --打印元表中的第一个元素print(entity_1.member_2)    --打印元表中的第二个元素
entity_1 = setmetatable( entity_1, {    --元表元素也可以是函数，一切都是变量
    __index = function(entity_1, key)
        if key == "key2"thenreturn"metatablevalue"elsereturnnil;
        endend })

print(entity_1.key2)

mymetatable = {}
mytable = setmetatable({key1 = "value_1"}, {__newindex = mymetatable})    --省略了 function(mymetatable, key, value)print(mytable.key1)

mytable.newkey_1 = "newvalue_2"print(mytable.newkey_1, mymetatable.newkey_1)    --nil, newvalue_2

son_entity = { son_member = "son_value", __index = { son_metamember = "son_metavalue"},
        __newindex = function(table, key, value)
        print(key.." is not exist.")
        end
    }

parent_entity = { parent_member = "parent_value" }
setmetatable(parent_entity, son_entity)

print(parent_entity.parent_member)
print(parent_entity.son_member)
print(parent_entity.son_metamember)
parent_entity.newkey = 1--output: parent_value、nil、son_metavalue、newkey is not exist

entity_1 = setmetatable( {1, 2, 3}, {
    __add = function(genericT, num)
    for k, v inipairs(genericT) do
        genericT[k] = v + num
        endreturn genericT
    end
})

--[[
entity_1 = setmetatable( {1, 2, 3}, {
    __add = function(genericT, num)
    for k, v in ipairs(genericT) do
        v = v + num        --最初的写法是这样
        print(v)        --这里打印的数据会被修改，但并不会真正改到 entity_1
        end                --可见lua的迭代器是值传递，还不是C#的引用传递
    return genericT
    end
})
]]--

entity_1 = entity_1 + 5for k, v inipairs(entity_1) do
    print(v)
end

person = { name = ""}
person = setmetatable( person, {
    __call = function(person, newname)
        person.name = newname
    end
})

person("Luakid")
print(person.name)