Lua初识之表的构造-六

Lua初识之表的构造

构造器是创建初始化表的表达式，表是Lua特有的功能强大的东西，最简单的构造函数是{}， 用来创建一个空表。可以直接出示化数组。

days = {"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"}

构造一个? days 表并初始化 （第一个元素索引为 1）

print(days[1]) -- Sunday

print(days[2])

print(days[3])

构造函数可以使用任何表达式初始化

tab = { math.sin(1),math.sin(2),math.sin(3),math.sin(4),math.sin(5)}

print(tab[1])
print(tab[2])

赋值型
a = {x = 2,y = 3}
print(a["x"])? -- 取值需要用双引号
print(a["y"])? --

--嵌套表
--[[polyLine = { color = "blue",thickNess = 2,point = 4,
???????????? { x = 0,y = 0},
??? { x = 1,y = 1},
??? { x = 2,y = 2},
??? { x = 3,y = 3}
}

print(polyLine["color"]) --> blue
print(polyLine[1].color) --> nil
print(polyLine[2])?????? --> table:012BB8A8
print(polyLine[1].x)???? --> 0
print(polyLine[2].x)???? --> 1
--]]

--[[opnames = { ["+"] = "add",["-"] = "sub"}
i = 20; s = "-"
a = { [i + 0] = s,[i + 1] = s .. s,[i + 2] = s .. s .. s}

print(opnames[s])? --> sub
print(a[20])?????? -->? -??? 取值不用双引号
print(a[22])?????? -->? -----]]

--[[
n1 = { x = 0,y = 0} -- n1?? n2? 等价
n2 = { ["x"] = "10",["y"] = "10"}??? -- 最好不要用数组下标从 0 开始，否则好多标准库用不了
print(n1["x"])? -- 0
print(n1["y"])? -- 0
print(n2["x"])? -- 10
print(n2["y"])? -- 10--]]

m1 = {"red","green","blue"}? -- m1? m2? 等价 m2 = {[1] = "red",[2] = "green",[3] = "blue"} print(m1[1])? -- red print(m1[2])? -- green print(m1[3])? -- blue print(m2[1])? -- red print(m2[2])? -- green print(m2[3])? -- blue