Lua:如何替换两个或多个重复的“?"带有空字符串的字符? [英] Lua: How do I replace two or more repeating "?" characters with an empty string?

问题描述

我尝试了以下操作:

local str = "???"
string.gsub(str, "(??)*", "")

但它会删除所有的'?'人物.我想要单曲?"未被取代，但不止一个'?'替换为空字符串.

but it removes all '?' characters. I'd like single '?' not replaced but more than one '?' replaced with an empty string.

例如:

"?" = not replaced
"??" = replaced
"???" = replaced

任何帮助将不胜感激.

推荐答案

问号在Lua模式中是神奇的:它们表示

Question marks are magic in Lua patterns: they mean 0 or 1 occurrence of the previous class. Lua escapes magic characters in patterns with the % character.

正确的任务模式是％?％?+ ，这意味着一次实际的?字符，然后是一个或多个实际的?字符(请参见上面链接中的 + 修饰符).

The correct pattern for your task is %?%?+, which means an actual ? character once, followed by one or more actual ? characters (see the + modifier in the link above).

此代码

function test(s)
    print(s,s:gsub("%?%?+","-"))
end

for n=0,4 do
    test("["..string.rep("?",n).."]")
end

输出

[]      []      0
[?]     [?]     0
[??]    [-]     1
[???]   [-]     1
[????]  [-]     1

其中-显示替换的位置.

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