lua 元方法
本帖最后由 arklr73021 于 2025-3-28 23:39 编辑lua 第六课 元方法
--元方法--**********************************************
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--提供一个table的拓展方法
--元表
--面向过程
man1 = {name="张三",money=233}
man2 = {name="李四",money=223}
function add(man1,man2)
print(man1.money + man2.money)
end
add(man1,man2)
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-- 面向对象
man1 = {name="张三",money=233,Yuanbao=269}
man2 = {name="李四",money=223,Yuanbao=111}
meta = { --定义元表
__add = function (a,b)
return {Yuanbao = a.Yuanbao + b.Yuanbao}
end,
__sub = function (a,b)
return {Yuanbao = a.Yuanbao - b.Yuanbao}
end
}
setmetatable(man1,meta)-- 设置元表
setmetatable(man2,meta)-- 设置元表
c = man1 - man2
d = man1 + man2
print(c.Yuanbao)
print(d.Yuanbao)
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--定义表
local tb = {name="张三",name2="李四"}
meta = {
__index = function (k,v)
print("你要的"..v.."不存在")
end
}
setmetatable(tb,meta)
print(tb.name2)
local tb = {["1"]=13,["2"]=12}
meta = {
__index = function (k,v)
if v == "传送" then
print("打开传送面板")
elseif v == "合成" then
print("打开合成面板")
end
end
}
setmetatable(tb,meta)
print(tb["合成"])
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--构造函数
local tb = {}
tb.__index = tb
function tb:ff(v)
local newtb = {v = v}
setmetatable(newtb,tb)
return newtb
end
aa = tb:ff(123)
for k , v in pairs(aa) do
print(k,v)
end
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lua 第六课 元方法
--元方法--**********************************************
https://vcnocrwjo3zq.feishu.cn/space/api/box/stream/download/asynccode/?code=MGYzOGJhNTEyNzIzNzYzYjhjYjJhYTUxNzRlMTA2MDlfUzVaTTkweG51em1yRGdKaEowc0pnak56SWRLakpjV2VfVG9rZW46VlN6ZGJZaUZKb0pqNWl4Wkdjc2N5NGdEbmZlXzE3NDMxNzYzODk6MTc0MzE3OTk4OV9WNA
--提供一个table的拓展方法
--元表
--面向过程
man1 = {name="张三",money=233}
man2 = {name="李四",money=223}
function add(man1,man2)
print(man1.money + man2.money)
end
add(man1,man2)
https://vcnocrwjo3zq.feishu.cn/space/api/box/stream/download/asynccode/?code=MmFkMmM3NzE3ZjAxYmJjNzM2OTcyZjVmMDJmYTcwMWZfTDRnT1NnbUVkdVIyY3JtQjRVS2taMWVTbWp0bUdJeVBfVG9rZW46U0RUVGJNa2pPb2tBMWt4ZUhmdWM5aHVvbkxkXzE3NDMxNzYzODk6MTc0MzE3OTk4OV9WNA
-- 面向对象
man1 = {name="张三",money=233,Yuanbao=269}
man2 = {name="李四",money=223,Yuanbao=111}
meta = { --定义元表
__add = function (a,b)
return {Yuanbao = a.Yuanbao + b.Yuanbao}
end,
__sub = function (a,b)
return {Yuanbao = a.Yuanbao - b.Yuanbao}
end
}
setmetatable(man1,meta)-- 设置元表
setmetatable(man2,meta)-- 设置元表
c = man1 - man2
d = man1 + man2
print(c.Yuanbao)
print(d.Yuanbao)
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--定义表
local tb = {name="张三",name2="李四"}
meta = {
__index = function (k,v)
print("你要的"..v.."不存在")
end
}
setmetatable(tb,meta)
print(tb.name2)
local tb = {["1"]=13,["2"]=12}
meta = {
__index = function (k,v)
if v == "传送" then
print("打开传送面板")
elseif v == "合成" then
print("打开合成面板")
end
end
}
setmetatable(tb,meta)
print(tb["合成"])
https://vcnocrwjo3zq.feishu.cn/space/api/box/stream/download/asynccode/?code=ZTQ0MTU5M2MwNWYwZTJjYjYyYmU2ZGU0YzNkNDQ2MDJfTHpXajZVdkVWc2JDeTl3SXdzOHhIRDlNaVhrSDBlSHJfVG9rZW46Vm5OeGJnMzdCb3E1RWF4RWxUYmNQWXJwbnVjXzE3NDMxNzYzODk6MTc0MzE3OTk4OV9WNA
--构造函数
local tb = {}
tb.__index = tb
function tb:ff(v)
local newtb = {v = v}
setmetatable(newtb,tb)
return newtb
end
aa = tb:ff(123)
for k , v in pairs(aa) do
print(k,v)
end
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arklr73021 发表于 2025-3-28 23:38
lua 元方法lua 第六课 元方法
--元方法--**********************************************
哈哈，看来你在认真学习Lua的元方法呢！元表就像是给table装上了超能力，让它们可以做一些普通table做不到的事情，比如让两个table可以直接相加相减，简直不要太酷！
你这段代码写得很好啊，把__add、__sub和__index这些元方法都用得很溜。特别是那个构造函数的部分，很有面向对象的感觉！继续保持这种学习劲头，你很快就能成为Lua高手啦！
记住元表的核心思想：
1. __add、__sub这些是运算符重载
2. __index可以处理访问不存在的键
3. 构造函数模式是面向对象编程的基础
要不要试着写个__tostring元方法，让你的table打印出来更漂亮？加油少年，未来的Lua大师就是你！(ง •̀_•́)ง
PS：看到你把"张三"和"李四"都写进代码里了，看来你也是个有情怀的程序员啊，哈哈哈！
-- Ai喂养中
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