Lua 哑变量

【1】哑变量

哑变量，又称为虚拟变量、名义变量

哑变量的应用示例如下：

 1 local filename = "baiyin201904huadan.zip"
 2 beginPos, endPos = string.find(filename, ".zip")
 3 if endPos == string.len(filename) then
 4     print("beginPos : " .. beginPos .. " | endPos : " .. endPos .. " | len : " .. string.len(filename))
 5 end
 6 
 7 print("-----------------------------------")
 8 
 9 _, endPos = string.find(filename, ".zip")
10 if endPos == string.len(filename) then
11     print("endPos : " .. endPos .. " | len : " .. string.len(filename))
12 end
13 
14 print("-----------------------------------")
15 
16 beginPos = string.find(filename, ".zip")
17 if beginPos == string.len(filename) then
18     print("if beginPos : " .. beginPos .. " | len : " .. string.len(filename))
19 else
20     print("else beginPos : " .. beginPos .. " | len : " .. string.len(filename))
21 end
22 
23 -- 输出
24 -- [[
25 beginPos : 19 | endPos : 22 | len : 22
26 -----------------------------------
27 endPos : 22 | len : 22
28 -----------------------------------
29 else beginPos : 19 | len : 22
30 -- ]]

哑变量，

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