Lua学习笔记二

小程序+输出说明

 

 

 

--1. 逻辑比较 >,>=,<,<=, ==, ~=
print( "---------1----------------")
print(3.14 ~= math.pi)      --> true

x = x or math.pi            -- 等价于 if not x then x = v end
print(x)

--2. table 初始化

print( "---------2----------------")
t1 = { color = "blue", own="ha"; "one", "two", "three", [4] = "four" }
print(t1.color)
print(#t1)
print(t1[1])


--3 循环语句中的局部变量作用域
print( "---------3----------------")
repeat
    local line = math.random(1, 10)
    print( line )
until line >= 8          --> 在循环条件中可以访问局部变量line

--4 table 的遍历
print( "---------4----------------")
for i in pairs(t1) do           --> 关联表数组全部打印
    print(i, t1[i])
end

print("----")
for i, v in ipairs(t1) do       --> 只打印数组
    print( i, v )
end

print("---")
t2 = {
    {name = "tafjk", ip = "192.168.8.1"},
    {name = "test", ip = "192.168.1.5"},
    {name = "my", ip = "192.168.201.1"},
}

-- table sort

for i in pairs(t2) do           --> 关联表数组全部打印
    print(i, t2[i].name, t2[i].ip)
end
print( "-" )
table.sort(t2, function (obj1,obj2) return (obj1.ip > obj2.ip ) end )
for i in pairs(t2) do           --> 关联表数组全部打印
    print(i, t2[i].name, t2[i].ip)
end

--5 函数返回值
--若函数调用时最后一个参数，则会返回所有返回值，否则，只返回一个值
print( "---------5----------------")
function foo()
    return 2009, 1
end

print( foo() )              --> 2009 1
print( ( foo() ) )          --> 2009
x = foo()
print( x )                  --> 2009

x,y,z = foo(), "foo"        --> 2009 foo nil
print(x, y, z)

print( unpack( { foo() } ) )    --> 2009 1,  unpack接受list参数，并从下标1开始返回

print( string.format("%d-%d-%s", 2009, 1, "lua") )  --> 2009-1-lua