如何在lua字符串中找到重复字符的索引

Question

假设你有这样的路 /home/user/dev/project 我想获得任何/的索引，我想要
就像我想要dev之前的一个或用户
之前的一个 如果有一个好的文档，请链接它

Answer 1

有几种方法可以做到这一点。也许最简单的是使用（）模式元素，该模式元素产生的匹配位置与string.gmatch：

for index in ("/home/user/dev/project"):gmatch"()/" do
    print(index)
end

它

1
6
11
15

按预期进行打印。要走的另一种方法（需要更多代码）将反复调用string.find，始终通过启动索引。

假设您可能想将字符串划分为斜线，则使用string.gmatch ：（

for substr in ("/home/user/dev/project"):gmatch"[^/]+" do
    print(substr)
end

字符串，最大长度不包含斜线的所有子字符）

该模式找到所有非零的子 IS 在这里。您可能想查看“捕获”小节。

Answer 2

有很多方法。
也很高兴知道LUA已将所有字符串函数连接为方法。
那就是@lmd用：直接在字符串上演示的内容。
我最喜欢尝试使用模式及其捕获的复杂/困难的地方的地方是Lua独立控制台：制作Linux-Readline

因此，让我们玩模式'[％/\\] [％u％l％s]+'

> _VERSION
Lua 5.4
> -- Lets set up a path
> path='/home/dev/project/folder with spaces mixed with one OR MORE Capitals in should not be ignored'
> -- I am curious /home exists so trying to have a look into
> os.execute('/bin/ls -Ah ' .. ('"%s"'):format(path:match('[%/\\][%u%l%s]+')));
knoppix  koyaanisqatsi
> -- OK now lets see if i can capture the last folder with the $
> io.stdout:write(('"%s"\n'):format(path:match('[%/\\][%u%l%s]+
))):flush();
"/folder with spaces mixed with one OR MORE Capitals in should not be ignored"
> -- Works too so now i want to know whats the depth is
> do local str, count = path:gsub('[%/\\][%u%l%s%_%-]+','"%1"\n') print(str) return count end
"/home"
"/dev"
"/project"
"/folder with spaces mixed with one OR MORE Capitals in should not be ignored"

4
> -- OK seems usefull lets check a windows path with it
> path='C:\\tmp\\Some Folder'
> do local str, count = path:gsub('[%/\\][%u%l%s]+','<%1>') print(str) return count end
C:<\tmp><\Some Folder>
2
> -- And that is what i mean with "many"
> -- But aware that only lower upper and space chars are handled
> -- So _ - and other chars has to be included by the pattern
> -- Like: '[%/\\][%u%l%s%_%-]+'
> path='C:\\tmp\\Some_Folder'
> do local str, count = path:gsub('[%/\\][%u%l%s%_%-]+','<%1>') print(str) return count end
C:<\tmp><\Some_Folder>
2
> path='C:\\tmp\\Some-Folder'
> do local str, count = path:gsub('[%/\\][%u%l%s%_%-]+','<%1>') print(str) return count end
C:<\tmp><\Some-Folder>
2